Web forum DB on localhost - can't login

[bang]

I'm trying to get my web forum db to work on localhost. Forum version installed on localhost is the same as on the web. Before importing I've changed the cookiedomain setting through phpMyAdmin. The board works fine with the new imported DB, but I can't login into the admincp. I login to the forums (that works in the beginning), click Admin, put in my password, click Login and get redirected to the login screen again. And again... If I try to go back to forums I appear logged out again. There is even no cookie file saved in my windows cookie dir. I've also tried setting the cookiedomain setting nothing (making it empry), but it did not work.