Blank Page

Hello,

I have installed the forum. It works weel and handle most of the features I need.
Still, I have a problem :
. Adding a thread / Message leads to a blank page. The content is created but it doesn't go to a "OK" page.
. Adding a new forum doesn't work. It also leads to a blank page, but the content is not created.

Do you see any reasons for that ?

Matthieu.