I can't login into DP forums

Can anyone please tell me why this could happen to me? I have trouble logging in for about two months now. When I attempt to login it brings me to that "please wait username while we redirect you" (something like that) redirecting page. But after a few moments it'll kick me back again to the main page without logging me in. It's persistent no matter what I do. My password works just fine I'm sure of that. I was definitely not banned or anything like that. I don't know why is this happening to me. It can't be the cookies cuz I've set to accept them. Can't be anti-spyware or firewall or any program of that kind cuz I also tried disabling them while logging in. I tried switching browsers and I also tried switching ISP to no avail. I also tried switching computers! Goodness. Though I was able to create a new username without reproducing the same problem. So I take it the problem is just really with these username? This happens about 90% of the time, but surprisingly I can get through sometimes (10%) like now.

I have the feeling that it might just happen again after I log out this time. Wish me luck!

I would really really appreciate any advice. Thanks.