bbPress.org

This works:

http://thomas.ipublish.no/wp-login.php

And this:

http://thomas.ipublish.no/forum/

BUT

With no trailing slash:

http://thomas.ipublish.no/wp-admin

redirects to:

http://thomas.ipublish.no/forum/wp-admin/

And gives a 500 Internal Server Error.

With the proper trailing slash:

http://thomas.ipublish.no/wp-admin/

redirects properly to:

http://thomas.ipublish.no/wp-login.php?redirect_to=http://thomas.ipublish.no/wp-admin/

I’d say it has something to do with the rewrite rules and the RewriteBase maybe, in one of the two .htaccess files, but without seeing the rules from both, it’s hard to say.