Subdomain problems

I can’t get any subdomains to work.

I have which I want to redirect to a different site (with the redirect setup through

I have which I want to use as a test site to upgrade my main install.

For both, firefox simply hangs up on with a Page Load Error saying “Redirect Loop: Firefox has detected that the server is redirecting the request for this address in a way that will never complete.” Note that I do not have an “install.php” file in ANY domain or subdomain.

My main install is a multisite-enabled Drupal install. Is it hijacking the subdomains before Dreamhost can see them? If so, how can I prevent it (i.e. let dreamhost check for other subdomains first)? What is going on?