Can't Create New Blogs

I’ve enabled the multisite option and have done the network set up as directed (updated the wp-config.php and the .htaccess). When I was prompted to login again I did, but when I go to Tools I don’t see a Network Admin option, I’m still seeing the Network Setup option. When I click on that again I’m taken to the “Create a Network of WordPress Sites” page again, but at the top of the page is a “Warning: An existing WordPress network was detected.” message. So it seems that I did get thing set up right, but I don’t seem to be able to create a new blog site. I’ve cleared my cache and gone through all the documentation I can find for my host (mediatemple) and what I can find here and in the Codex, but I haven’t been able to find any answers.

Thanks for any suggestions.