Thanks Arthur. I read through the post you linked (I'm having the same problem) and several others dealing with .htaccess files and couldn't find a solution. I think the thread you linked to was closed before being resolved.
Any other ideas? I would start over but I wouldn't know anything to do differently in the install. It seemed pretty straightforward up until the redirect.
What seems especially odd to me is that I can access additional sites that I create but they display as plain HTML without CSS. I can see the sites (sans CSS) but can't access their dashboards.