403 Forbidden with Codeigniter on Ubuntu

[eluser]AoiKage[/eluser]
I've recently switched back to Ubuntu (10.10) and I have a problem. I installed the usual lamp-server package and everything works fine. Every PHP app, CMS etc works, but I can't access any codeigniter folder (403 forbidden). I have a fresh installation and a folder with a little site I was developing using codeigniter and both of them give me that error. The app I was building uses a .htaccess, but the fresh installation doesn't, so I think the problem is not in the mod_rewrite (which, btw, is active).