Problem with log in

Hello everyone,
I install WP 2.7.1 some days ago. Everything was good, but I can’t log in, into my administration panel. I write correctly nick and password, I see main page for 1-2 second, but then it started to reloading and that’s it. I see white page which is still loading. I try everything, but nothing help me. However, when I try to edit post, I can do this and then I’m in administration panel. I can do everything, upload photos, add new post, change theme; without see main page of it. Weird….Any ideas? I have polish hosting: hosting.osemka.pl