about cookies in advanced poll....

Well everything works just fine but..
after voting page won't load...it's loading too long and u gotta stop it . Close the window! (refresh doesnt help) and then when u open page again sometimes u can vote again, sometimes it says "u already voted" but ur voice is counted anyway... so i think it's the cookie problem.
Can u help me out with fixing it?
Site is complitely on PHP.