Membership plugin won't recognize dedicated ip

Hello,
I am currently trying to set up the Membership plugin but have run into a bit of a problem. Right now we are working off a dedicated ip address until the site is ready and will then switch the DNS to point to the new site. The problem is that I'm getting this message when I try to access the sign-up page:

Warning: require_once(cmsAdmin/lib/viewer_functions.php) [function.require-once]: failed to open stream: No such file or directory in /home/davgol20/goldcastleholdings.com/login/signup.php on line 2

Fatal error: require_once() [function.require]: Failed opening required 'cmsAdmin/lib/viewer_functions.php' (include_path='.:/usr/local/lib/php:/usr/local/php5/lib/pear') in /home/davgol20/goldcastleholdings.com/login/signup.php on line 2

Now i think the problem lies where it says goldcastleholdings.com. Since the domain hasn't been switched over yet and we are using the dedicated ip instead it is choking. Is there a way I can get this to work using a dedicated ip instead of the actual domain name? I hope I'm being clear.