@gerikg: I had pretty much given up on this an age ago after trying every listed trick on these forums at the time. Your solution worked flawlessly, so thank you very much!
sambauers posted this in another thread:
Oh, I forgot, add this to your bb-config.php
define(‘WP_AUTH_COOKIE_VERSION’, 1);
When you upgrade to WordPress 2.8 later, you will need to remove that line.
Worked like a charm for me!
I’m in the same boat. I’ve tried every suggestion I’ve come across in the forums, the cookie hashes match, the settings match, and still it refuses to work. It’s rather frustrating to say the least.