Google not crawling my site.

This is something I'm having a problem with.  I'm running a number of sites using Rainbow and Google is refusing to crawl them.  Google fetches the root page /default.asp, which redirects to Rainbow's main page (the content management system I'm using), which returns the top page for that site, and then Google stops. 

On each of the sites I have a link to a Site Map page that has plain links to all the parts of the site, and I have no idea what's turning Google away.  Of course their algorithms are proprietary and secret, so I'm stuck with trying to figure out what's going on by simply changing things and waiting a few days to see if it helps.