BuddyPress: Registration not working on Internet Explorer

OK, I'm stuck.. been searching for a solution for days and have finally come back to my most reliable source. We have a site we are building for a client that is having Buddypress registration issues in Internet Explorer. Some members are able to register after a few tries, some have tried 20 times with no luck. I'm on a mac and unable to duplicate the issue, but after so many people complaining, it's a real issue. Seems to work fine in other browsers for the most part, especially on a mac.

After a new user registers on IE, the page essentially refreshes and never submits. Passwords are cleared out and they try again. No activation email is ever sent as the registration is never completed. I've had users clear cache's and cookies and no success.

We have only one plugin running (WPMU's Sign Up Code) beyond that, nothing is running additionally. WP and WPMU and Buddypress are all up to date with the most current versions.

Has anyone ever seen this or have an idea of how to resolve the issue? I'm stumped.

If anyone would like to test it out, the registration can be found at http://metrodenveridc.com/register/ and the sign up code is 1234

Thank you so much in advance for your time and assistance -

Matt