Error when trying to Activate a New Site

The site is Joviehost.com just started hosted on a VPS with Bluehost. I have successfully setup WP Multisites and installed the Pro Sites Plugin.

I am using subdomains and have setup the wildcard in Bluehost for Joviehost.com as *.joviehost.com

When I try to activate a new site I receive the "500 Internal Server" error.

Am I missing a setting somewhere?

Thanks,
Paul