Cannot Modify Header

I get this error when I I try to login or register:

Warning: Cannot modify header information – headers already sent by (output started at /home/harisnt/public_html/blog/wp-includes/pluggable.php:522) in /home/harisnt/public_html/blog/wp-login.php on line 13

this was all working fine, but today morning i accidentally deleted my database. But I had the backup as usual. I restored it through phpMyAdmin. But now, I can’t login or register a new account. I get his error on the login/register page.

You can see the problem yourself at: http://sizzledcore.uni.cc/blog/wp-admin/

I need to fix his urgently. Someone please help me! I’m using WordPress 2.1.2