Attach to your sql database weither that be a *.mdf file (ex. Database.mdf) or a sql database on a server with Microsoft SQL Server Management Studio Express, and browse to the Programmability folder, then Stored Procedures, and finally find the Forum_SearchGetResults right click and select modify.  Edit the @Filter + ... line for me it was on line 45.  It should read:

@Filter + ' GROUP BY P.ThreadID , P.CreatedDate ORDER BY P.CreatedDate DESC '

and you should re-write it to read:

@Filter + ' GROUP BY P.ThreadID , P.CreatedDate ORDER BY P.ThreadID '

You can then save it to a .sql file but to commit the changes you must press the Execute button

Worked for me.

Thanks