Issues with registered domain name pointing to Machine IP

I have developed an ASP.NET application. Tested it on the net with the machine's IP address. Now that the application is golden, I have associated the web application with a purchased domain name. But now, when I go to the web site through the internet domain name, the server-sided aspx scripts aren't getting executed.
No idea where to start with this issue or even how to look it up.
Is this something I need to fix on the machine hosting the application, or with the domain name and how its pointed to my machine?

Thanks for all help on this issue.

unfortunately, we're probably going to need more information.

What version of IIS are you running? (What versions of Windows)
Are the name servers set up to point the domain name to the correct server?
When did you set up the name servers? (It can take up to 48 hours to propogate. If you just bought it, it won't work right away.)
Is there a firewall in the way?

As you can see there are a number of things that could potentially cause this.

Thanks for responding wayneph.
Well, the IIS is 6.0 running on Microsoft Windows Server 2003. I am assuming that the name server is pointed correctly because when you go to the web address, the page will be displayed. It seems all javascript works just fine, but the server-side scripting doesn't (ASP.NET). The domain was purchased on Friday and there is a firewall, but when the web IP was used to develop the application, I have not ran into any of these issues.

Are there multiple sites on your machine that are all responding to the same IP Address? If so, you may need to add the domain name in to the Headers for the specific site you want.

There isn't a setting that I know of that would make a site react differently for an IP Addres vs. a name. If you ping the domain name, does it point to the correct server? Does it work if you're outside the firewall, but not from inside the firewall? It could be that you need to use a HOST file to prevent going through the firewall twice...