That's pretty quick for DNS. How about creating a Mirror of that domain. Go to the Panel under Domains -> Manage Domains and create a Mirror called something like johnyb.dreamhosters.com and then use that for finishing the installation. "dreamhosters.com" DNS updates much faster than any brand new domain, since it's a subdomain.
Next, FTP to your account and just see if the domain.com folder looks fully populated. It probably is. I more suspect it's a DNS issue than a One-Click issue.
Or maybe it'll magically work for you after a few hours has gone by.