When my members click 'Log In' they are directed

This is a BuddyPress site.
I am running BlogsMU.

When my members click 'Log In' they are directed to "/custom-login" page - (this is good).

Once they place their username / password they are then sent to "/wp-login.php" where they have to place their username / password in again to gain access - (this is bad).

It appears that "/custom-login" is not registering with wordpress.

Whats the problem here?