camera collision problem

Hi.

I'm trying to prevent my camera to go into walls so you can't see trough them (that's what i and my friends call the Harry Potter bug because it is lots of it in that game).

i'm using a modified version of the original mouseorbit n unity http://rafb.net/p/7pGs9395.html

i know its not working with colliders because the script tells the camera to have the angle on fixedupdate/update.

Please help!!!!!