Login script, session problem (I think)

I made a simple login script which uses MySQL for username and password retrieval and that stores the username in a session, the problem is that this script only works locally, e.g. I can only login from this computer but not from any other, I have session.use_cookies = 1 and I also have another session on the page that stores a counted var so the counter doesn't jump up everytime someone changes page. The thing confusing me is that the counter session works global but the login only works local.. Does anyone have an idea how I should solve this? I'm not so good with php yet so I might have missed something, but i think it's wierd anyway... :p please reply as soon as possible. :) Hawk