XF 1.2 [FIXED] Trying to post when suddenly, error stacktrace!


I just finished managing my forums, using the latest XenForo update. Everything went fine except when I tried to post a message I got this:

Screen Shot 2013-12-10 at 11.27.24 AM.png

Anyone has an idea about how to prevent/fix this?

Thanks a lot and have a nice day.