Thanks. In the meanwhile I've edited the template file manually (argh!)

I've started a complete new installation, new database, new mysql user, new site.

But this doesn't help me to solve the problem.

Don't you think that following your solution nothing should work on the forum ? I have instead only this problem.

Does anyone help mi find the include file and line in php that read title's forum ? I'll try to solve myself and tell you.