Similar problem to Sentret. I tried to categorize a fanfic I wrote by Pokemon, and got this message.
Fatal error: Call to undefined function grab() in /home/pkmn/public_html/fanfics/savepokemon.php on line 20
I'm sorry to be the one to find problems with everything ::)
Should be a harmless error - it just tries to redirect you back to a different page after it has finished saving.
I'll put a fix in place