you are using wp super cache, have you told it to ignore and not cache the wp page the forum is on??  you cannot cache the forum…

sorry, as a matter of policy, we do not create accounts as we would have them floating around all over…

so, if not the caching, who does not see new topics??  admins? users? mods?  guests? are you moderating posts?  what permissions do you have set in the view grouping?

Mr Papa you are totally right, I installed wp super cache yesterday!

Now I have to figure out how to set this plugin to leave the forum alone. 

I deactivated the plugin to make sure the problem is with wp super cache but I still have problems.

When I create a new topic it will only appears to me if I logout and login again from the forum.

Also all users need to cycle their log status too in other to be able to see new topics and new posts…

Yes there is something to do with wp super cache, after a completly uninstall forum is working normal again.

would guys help me setting super cache to let the forum working properly?

You should have an exemptions tab or panel on the plugin option. It should be enough to put the forum slug (the permalink basically) in that exemption list. As far as I am aware that should be it for ‘wp super cache’. But hopefully Steve will chime in if there is more to do.