Domain Mapping Issue

OK…I have been searching the forums for two days. I set up hosting at psek and have parked my domains. I set up A name at godaddy. My domains (www.domain1.com) are forwarding correctly to the main server for my wpmu site (www.domain.com). Every time I add a site, it adds the site but only directs to the main domain name.

I can add the domain fine and it gives me http://www.domain.com/domain1. However, when I try to go into the custom domain panel to add the domain, it doesn’t allow me to add the custom domain for it to direct properly.

Hope this makes sense. I thought this would be easy!