Reformulating EF4 query to avoid parsing error?

How can I reformulate an Entity Data Model query to work around a parsing error? Here is the query:

    var selectedNotes = notes
        .Where(n => n.Tags.Count == 0)

And here is the exception that is being thrown:

There was an error parsing the query. [ Token line number = 12,Token line offset = 53,Token in error = AS ]

Here is the background to my problem:

I am working on an app that uses Entity Framework 4. The app organizes rich-text documents, called Notes, which are searchable by Tags, like blog entries. One of my Entity Data Model queries retrieves only Notes that have no Tags:

searchResults = DataStore.ObjectContext.Notes.WhereContainsNoTags();

WhereContainsNoTags() is written as a LINQ extension method, and it contains the lambda expression for the query:

public static IQueryable<Note> WhereContainsNoTags(this IQueryable<Note> notes)
{
    IQue开发者_如何学JAVAryable<Note> results;

    // Select Notes that contain no search Tags
    var selectedNotes = notes
        .Where(n => n.Tags.Count == 0)
        .OrderBy(n => n.Title);
    results = selectedNotes;

    // Set return value
    return results;
}

For simplicity, I have omitted the try-catch block that wraps the lambda expression and the logging code that logs any errors.

Here is the odd part: The query runs fine on my development machine, but it throws the above exception on the test machine. I have several other queries (match all Tags, match any Tags, and so on) that run fine on both the development and test machines.

I am quessing that the exception relates to the SQL generated by the EDM query. Is that the case? What is the best workaround? Is there a way to reformulate the lambda expression to avoid the problem?

Thanks for your help.

var selectedNotes = notes.Where(n => !n.Tags.Any())