Below are the code changes for BaseDynamicFileTree.cs, CreateScript.ascx.cs, CreateStyleSheet.ascx.cs:

BaseDynamicFileTree.cs

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text;
using System.Web;
using umbraco.cms.presentation.Trees;
using Umbraco.Core.IO;
using Optimus.Extensions;
using umbraco.interfaces;
using umbraco.BusinessLogic.Actions;
using Optimus.Enums;

namespace Optimus.Umbraco.Trees
{
    public abstract class BaseDynamicFileTree : BaseTree
    {
        public abstract TranslatorType TranslatorType { get; }

        public BaseDynamicFileTree(string application) : base(application) { }

        public override void RenderJS(ref StringBuilder Javascript)
        {
            Javascript.Append(
                TranslatorType == TranslatorType.StyleSheet ?
            @"
                function openDyanmicCSSFileEditor(fileName, compiled) {
                    UmbClientMgr.contentFrame('../App_Plugins/Optimus/Pages/FileEditor.aspx?file='+ fileName + '&path=/css/&compiled=' + compiled);
                }"
            :
             @"
                function openDyanmicScriptFileEditor(fileName, compiled) {
                    UmbClientMgr.contentFrame('../App_Plugins/Optimus/Pages/FileEditor.aspx?file='+ fileName + '&path=/scripts/&compiled=' + compiled);
                }"
            );
        }

        public override void Render(ref XmlTree tree)
        {
            string FilePath = TranslatorType == Enums.TranslatorType.StyleSheet ? "/css/" : "/scripts/";
            string orgPath = String.Empty;
            string path = String.Empty;

            if (!string.IsNullOrEmpty(this.NodeKey))
            {
                orgPath = this.NodeKey;
                path = IOHelper.MapPath(FilePath + orgPath);
                orgPath += "/";
            }
            else
            {
                path = IOHelper.MapPath(FilePath);
            }

            DirectoryInfo dirInfo = new DirectoryInfo(path);
            DirectoryInfo[] dirInfos = dirInfo.GetDirectories();
            var allowedExts = new Translation.Core().GetPossibleExtensions(TranslatorType).ToArray();

            var args = new TreeEventArgs(tree);
            OnBeforeTreeRender(dirInfo, args);

            foreach (DirectoryInfo dir in dirInfos)
            {
                if ((dir.Attributes & FileAttributes.Hidden) == 0)
                {
                    XmlTreeNode xDirNode = XmlTreeNode.Create(this);
                    xDirNode.NodeID = orgPath + dir.Name;
                    xDirNode.NodeType = TranslatorType == Enums.TranslatorType.StyleSheet ? "initstylesheetsNew" : "initscriptsNew";
                    xDirNode.Menu = new List(new IAction[] { ActionDelete.Instance, ContextMenuSeperator.Instance, ActionNew.Instance, ContextMenuSeperator.Instance, ActionRefresh.Instance });
                    xDirNode.Text = dir.Name;
                    xDirNode.Source = GetTreeServiceUrl(orgPath + dir.Name);
                    xDirNode.Icon = FolderIcon;
                    xDirNode.OpenIcon = FolderIconOpen;
                    xDirNode.HasChildren = dir.GetFiles().Length > 0 || dir.GetDirectories().Length > 0;

                    OnRenderFolderNode(ref xDirNode);
                    OnBeforeNodeRender(ref tree, ref xDirNode, EventArgs.Empty);
                    if (xDirNode != null)
                    {
                        tree.Add(xDirNode);
                        OnAfterNodeRender(ref tree, ref xDirNode, EventArgs.Empty);
                    }
                }
            }

            FileInfo[] fileInfo = dirInfo.GetFiles("*.*");
            foreach (FileInfo file in fileInfo)
            {
                if ((file.Attributes & FileAttributes.Hidden) == 0 && allowedExts.Contains(file.Extension))
                {
                    XmlTreeNode xFileNode = XmlTreeNode.Create(this);
                    xFileNode.NodeID = orgPath + file.Name;
                    xFileNode.Text = file.Name;
                    xFileNode.Icon = new Optimus.Translation.Core().GetTranslatorTreeIconPath(file.Name);
                    xFileNode.OpenIcon = "doc.gif";
                    xFileNode.Menu = new List { ActionDelete.Instance };
                    xFileNode.NodeType = TranslatorType == Enums.TranslatorType.StyleSheet ? "initstylesheetsNew" : "initscriptsNew";

                    if (string.IsNullOrEmpty(xFileNode.Action))
                    {
                        if (orgPath != string.Empty)
                        {
                            xFileNode.Action = TranslatorType == Enums.TranslatorType.StyleSheet ?
                                "javascript:openDyanmicCSSFileEditor('" + orgPath + file.Name + "', 'false');" :
                                "javascript:openDyanmicScriptFileEditor('" + orgPath + file.Name + "', 'false');";
                        }
                        else
                        {
                            xFileNode.Action = TranslatorType == Enums.TranslatorType.StyleSheet ?
                                "javascript:openDyanmicCSSFileEditor('" + file.Name + "', 'false');" :
                                "javascript:openDyanmicScriptFileEditor('" + file.Name + "', 'false');";
                        }
                    }

                    OnRenderFileNode(ref xFileNode);
                    OnBeforeNodeRender(ref tree, ref xFileNode, EventArgs.Empty);
                    if (xFileNode != null)
                    {
                        tree.Add(xFileNode);
                        OnAfterNodeRender(ref tree, ref xFileNode, EventArgs.Empty);
                    }
                }
            }
            OnAfterTreeRender(dirInfo, args);
        }

        ///
        /// Inheritors can override this method to modify the file node that is created.
        ///
        ///
        protected virtual void OnRenderFileNode(ref XmlTreeNode xNode) { }

        ///
        /// Inheritors can override this method to modify the folder node that is created.
        ///
        ///
        protected virtual void OnRenderFolderNode(ref XmlTreeNode xNode) { }

        protected override void CreateRootNode(ref XmlTreeNode rootNode)
        {
            rootNode.Icon       = ".sprTreeFolder";
            rootNode.OpenIcon   = ".sprTreeFolder_o";
            rootNode.NodeID     = "init";
            rootNode.NodeType   = rootNode.NodeID + TreeAlias;
            rootNode.Menu       = new List { ActionNew.Instance, ActionRefresh.Instance };
        }
    }
}

CreateScript.ascx.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using umbraco;
using umbraco.BasePages;
using System.IO;

namespace Optimus.Umbraco.Dialogs
{
    public partial class CreateScript : System.Web.UI.UserControl
    {
        protected void Page_Load(object sender, EventArgs e)
        {
            sbmt.Text = ui.Text("create");

            if (!Page.IsPostBack)
            {
                //scriptType.Items.Add(new ListItem("Plain script", "js"));

                scriptType.Items.Add(new ListItem(ui.Text("folder"), ""));
                scriptType.Items.FindByText(ui.Text("folder")).Selected = true;

                foreach (var trans in new Translation.Core().GetScriptTranslators())
                {
                    scriptType.Items.Add(new ListItem(trans.Name, trans.FileExtension));
                }
            }
        }

        protected void sbmt_Click(object sender, EventArgs e)
        {
            if (Page.IsValid)
            {
                //get file new path info
                var fileName = !String.IsNullOrEmpty(scriptType.SelectedValue) ? rename.Text + "."
                    + scriptType.SelectedValue : rename.Text;
                var helperPath = helper.Request("nodeID") == "init" ? String.Empty : helper.Request("nodeID");
                var cmsPath = !String.IsNullOrEmpty(helperPath) ? ("/scripts/" + helperPath + "/") : "/scripts/";
                var fullFilePath = Server.MapPath(cmsPath) + fileName;

                //make sure not create folder
                if (!String.IsNullOrEmpty(scriptType.SelectedValue))
                {
                    //create new file
                    File.Create(fullFilePath).Close();

                    //redirect to new file edit mode
                    BasePage.Current.ClientTools
                        .ChangeContentFrameUrl(".." + Config.EditFilePagePath + "?file=" + fileName + "&path=" + cmsPath)
                        .ChildNodeCreated()
                        .CloseModalWindow();
                }
                else
                {
                    //create new directory if not already exists
                    if (!Directory.Exists(fullFilePath))
                        Directory.CreateDirectory(fullFilePath);

                    //redirect to new file edit mode
                    BasePage.Current.ClientTools
                        .ChildNodeCreated()
                        .CloseModalWindow();
                }
            }
        }
    }
}

CreateStyleSheet.ascx.cs

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using umbraco;
using umbraco.BasePages;
using umbraco.cms.helpers;
using umbraco.BasePages;
using umbraco.IO;

namespace Optimus.Umbraco.Dialogs
{
    public partial class CreateStyleSheet : System.Web.UI.UserControl
    {
        protected void Page_Load(object sender, EventArgs e)
        {
            sbmt.Text = ui.Text("create");

            if (!Page.IsPostBack)
            {
                //styleSheetType.Items.Add(new ListItem("Plain stylesheet", "css"));

                styleSheetType.Items.Add(new ListItem(ui.Text("folder"), ""));
                styleSheetType.Items.FindByText(ui.Text("folder")).Selected = true;

                foreach (var trans in new Translation.Core().GetStyleSheetTranslators())
                {
                    styleSheetType.Items.Add(new ListItem(trans.Name, trans.FileExtension));
                }
            }
        }

        protected void sbmt_Click(object sender, EventArgs e)
        {
            if (Page.IsValid)
            {
                //get file new path info
                var fileName = !String.IsNullOrEmpty(styleSheetType.SelectedValue) ? rename.Text + "."
                    + styleSheetType.SelectedValue : rename.Text;
                var helperPath = helper.Request("nodeID") == "init" ? String.Empty : helper.Request("nodeID");
                var cmsPath = !String.IsNullOrEmpty(helperPath) ? ("/css/" + helperPath + "/") : "/css/";
                var fullFilePath = Server.MapPath(cmsPath) + fileName;

                //make sure not create folder
                if (!String.IsNullOrEmpty(styleSheetType.SelectedValue))
                {
                    //create new file
                    File.Create(fullFilePath).Close();

                    //redirect to new file edit mode
                    BasePage.Current.ClientTools
                        .ChangeContentFrameUrl(".." + Config.EditFilePagePath + "?file=" + fileName + "&path=" + cmsPath)
                        .ChildNodeCreated()
                        .CloseModalWindow();
                }
                else
                {
                    //create new directory if not already exists
                    if (!Directory.Exists(fullFilePath))
                        Directory.CreateDirectory(fullFilePath);

                    //redirect to new file edit mode
                    BasePage.Current.ClientTools
                        .ChildNodeCreated()
                        .CloseModalWindow();
                }
            }
        }
    }
}