Occasionally I only get the page mydomain.com/fblogin.php and a blank page (using any browser). I notice a significant drop in traffic from using this plugin, yet not a single user has signed up using it (except me) - so it must be interfering with something.
Edit: The update to 1.1.1 seems to fix this problem.
However the login does not trigger when used in for example the vB Links Directory, as here:
http://hypography.com/links/