An Error Has Occurred!

[nathan89]

When an annonomous user post on my forum this error comes up.  The post still go through however this error comes up everytime.  Any suggestions as to what may be causing this?

An Error Has Occurred!
This topic doesn't exist on this board. 

[nathan89]

I completely reinstalled my forum, leaving of course the SQL database intact, and the error is still appearing.  The only mod installed right now is Simple Portal.

[greyknight17]

Did you do the following already?

Go into Admin->Forum Maintenance and run the following:

Optimize all tables to improve performance.
Find and repair any errors.
Recount all forum totals and statistics.