> How about a new forum system without the treeview for the 
> messages. The treeview is a little bit too complex. There 
> are many good free forums out there (like XMB, YabbSE, 
> phpBB, Invision).

Well, why not - but such things is quite time-consumming, 
and the forum works (even with bugs, like responses not 
appearing if the thread is too old) relatively well. I did 
not yet find the perfect solution (pretty, easy to 
maintain, practical..)