Can we start with the error log (in the toolbox admin menu section). Clear it out please using the button at the bottom. Then try and edit a topic title. Save as you would. Then go refresh the error log to see if anything is reported. Interested in actual errors or SQL/Database entries - the pink ones.
I did that. No pink errors showed up. Only this notice:
not sure you posted the entire message???
how are you editing the title? the forum tools?
your message only says
SP Error Log
looks like the image didnt upload...