The maximum amount of time for a script to execute was exceeded. You can change this limit by specifying a new value for the property Server.ScriptTimeout or by changing the value in the IIS administration tools.
The default was made much snappier at the same time as I added full text search for the bigger forums. I forgot to mention that fact at the time. I've disabled full text search on this and your forum for the time being because of performance problems which I have yet to iron out. If you try it on your forum it should return no results.