Sounds like a permission/configuration problem on your QA server, are you using IIS6 or IIS7?
From a recent struggle I had, I'd say you're using IIS6 and forgot to add the wildcard mapping to your configuration.
- Right click your website in the IIS manager.
- On the 'home directory' tab click 'configuration'.
- Add the bottom you'll see wildcard application maps,
- Insert %windir%\Microsoft.NET\Framework\v4.0.30319\aspnet_isapi.dll (or \Framework64\ if its 64bits).