MU wp-signup.php loop/redirect - reward offered for fix!

Need some help. For some reason our registration:

http://yovia.com/blogs/wp-signup.php redirects to either http://yovia.com/blogs or http://yovia.com/blogs/register.

Looked in htacces file and wp-settings.php as well as wp-config.php. Anyone have any ideas???

Driving us crazy! Offering a "reward" to anyone who knows where to look to solve this. Also looking to hire someone to integrate Gigya Socialize plugin.