/~ username format for new site breaks admin (cpanel)

Below is what the host wrote me regarding my inability to log in to the admin area. I set up a site without moving the DNS to the server in order to build it first. Usually you access the site using /~ username when the DNS is not pointed. It doesn't work with gallery. Any help? Below is what the host wrote: (We attempted to modify the baseURL in the config file)

Unfortunately, this appears to be a bug in the gallery code in relation to ~username urls. As you can see, the auto-detection fails because it strips out ~paytonwr. Manually setting it to http://mclaren.websitewelcome.com/~peytonwr/art/index.php fails because it needs main.php for other things, and setting it to http://mclaren.websitewelcome.com/~peytonwr/art/ fails in a similar way. This is not due to a problem with the server. I've tried maybe 5 variations with no results. I would contact the Gallery maintainers, or at least setup a normal subdomain like test.domainname.com for the URL to avoid the ~username issue in gallery.