If you are receiving an error when attempting to use the 'My Posts' within the DNN forum module, this article will explain how to correct this problem.
You will need to be able to remotely connect to your database using a 3rd party SQL client such as "SQL Management Studio Express" which is free to download from Microsoft.
Connect to your database using your 3rd party SQL client. Then 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. Please note that this bug and fix were originally found for DNN version 4.5.3. We are not sure if this has been fixed in later DNN versions.