Redirection loop after enabling FacebookConnect

[pw2467]

I am getting the following message after successfully authenticated with FB:

The page isn't redirecting properly
Firefox has detected that the server is redirecting the request for this address in a way that will never complete.

This is the link that creates the issue:

http://www.myforum.com/forum/register.php?code=[removed]

The forum is installed under myforum.com/forum directory. The .htaccess has the following:

RewriteCond %{HTTP_HOST} ^hsfishingforum\.com$
RewriteRule (.*) http://www.hsfishingforum.com/$1 [R=301,L]
RewriteRule ^$ /forum/forum.php [L]

Tried to remove the last line, but it didn't help. Site URL under VB options is set to: "http://www.myforum.com/forum". I used the same in FB configuration.

Any ideas?