BP Social Theme | Pro Site | Membership

Hi All!

I am using the BP Social theme for a multisite network.
My ultimate goal is to:

1. Have a Pro Site where visitors would have to pay before getting a site.
2. Have this Pro Site include a Membership where users can access members only pages, interact via Buddy Press, and be able to blog on their site.

I have the Buddy Press and Pro Site plugins installed with 'Pay Before Blog' enabled, but I'm getting this error on the register page at the bottom:

Fatal error: Call to undefined function bp_blogs_subdomain_base() in /home/content/95/10424995/html/main/wp-content/themes/bp-social/registration/register.php on line 216

When you go to my homepage: http://hire-yourself.com you are presented with an option to signup. That link is broken.

I'm also confused on the flow for a visitor.

When someone registers using the BP register page, will they then be redirected to the Pro Site checkout to pay?
How do I integrate the Membership plugin with this process?

Am I going about this the wrong way?

Thanks guys/gals,