ProSites + BuddyPress + MarketPress Not Working Properly

I followed the step-by-step directions to set up a multi-site. Then I installed BuddyPress and MarketPress. At first things seemed to work fine, but when I try to create a new site from the network panel (or a user tries to create one from the front) the site does not seem to get created. The link in the email sent gives an error “can’t find the server” or takes me to a “404 Page Not Found” error.

Can you walk me through this or is it possible to hire someone to take a look? I’m new to WPMU DEV and thought I could hire someone but can’t find a link/way to do so.