I've installed version 1.4.21. After registering with Facebook I'm redirected to the home page. My account has been created, I'm logged in, everything seems to be fine.
Immediately after that I try to access the profile settings page (/wp-admin/profile.php) but I get the following error: "You do not have sufficient permissions to access this page."
The weird thing is, that 5 minutes after completing the registration process everything is working fine.
You can check out this issue here: funelf.net