WordPress not working after transfer

Hello,
I just transfered my wordpress (file and database backup) to a new host (not a webhost, a linux vps server with installed lamp stack). Everything is installed, created database and imported my old one into it, updated wp-config with new database name, mysql user and password, transfered domain etc.

I can log in to wp-admin and my homepage works fine. mydomain/forums works too, but I cannot login into it. Even if I’m logged in on the homepage, I am logged out in bbpress. If I log in to bbpress, it just sends me back to my homepage.
Other pages do not work (404).

What did I miss here? The database seems to be working since I have all my posts, users etc. So what’s the problem?

EDIT:
If I set permalinks to default, it will open the pages, but forums still don’t work. Also created a new .htaccess file to let wordpress generate the settings, still nothing. I need permalinks to be set to post name, and to be able to log in to the forum.