I am using an examin index for searching members and I am trying to set it up so I can sort on a custom property (lastName).

@using Examine;
@using UmbracoExamine;

@{
    var searchTerm = Request.QueryString["q"];                          //Get the search term from query string
   
    var criteria = ExamineManager.Instance
            .SearchProviderCollection["MyMemberSearcher"]
            .CreateSearchCriteria(UmbracoExamine.IndexTypes.Member);

    var filter = criteria.Field("profileIsPublic", "1").OrderBy(new string[] { "lastName" });
}

I am getting an error that states:

'Examine.SearchCriteria.IBooleanOperation' does not contain a definition for 'OrderBy' and no extension method 'OrderBy' accepting a first argument of type 'Examine.SearchCriteria.IBooleanOperation' could be found.

I have checked my Examine DLL and it indeed has the OrderBy() extension method in the IQuery public interface.  (same location as the Field() ext method which I am using in my filter too).  I have even downloaded the latest DLLs from Examine on codeplex but I havent been able to get past this issue.  Any ideas?