While trying to post a message to the GSoC forum (after writing the message and clicking on "Post"), I got the error "Fatal error: Call to a member function setField() on a non-object in /sites/ssopen/www/forum/code/Forum.php on line 641" - see screenshot below.
I did nothing special, maybe too much time passed between opening the reply window and actually posting?
I just waited for another 10 minutes on this post and got the same error, when posting immediately it seems to work...