BuddyPress.org

@dpee

Is this a new Installation of mu, I mean, Mu is installed on your root domain http://mysportspress.com

or http://mysportspress.com/wordpress-mu/

If Mu is not on root domain, you may not use subdomain style blogs, In that case You will have to go for category style sub blogs.

If Mu is on root domain, follow what @Obuisson1976 has mentioned, or just create a wild card subdomain, (i.e. *) in your cpanel->subdomains.

That should make it work.