Multisite, Buddypress & Marketpress - Registered Users can't Create Site

I'm currently stuck with a problem that i can't seem to find the answer to anywhere on the internet, essentially i have a Wordpress Multisite activated with Buddypress and Marketpress, the system itself works fine but there's one big problem and that is that once a user is registered they can no longer create a site and i can't quite figure out why.

When you use the create site options it just takes you here and presents you with:-

Not Found

Nothing found for the requested page. Try a search instead?

Any help on how to sort this would be very greatly appreciated

Kind Regards