Well, I just installed PCLinuxOS, installed my printer and that's all. There are two normal users and the root. Everyone can print, but I didn't specify anything about users in the CUPS setup.
I also did some more tests and it seems those files get printed, but it takes ages - about 5 minutes per 2 page pdf it's far too much for me.
If you need any more data to help, please tell me what should I provide.