I have done installations on x64 which worked fine.
Here are some checkpoints I normally use.
- Install IIS first
- Install the .NET 2.0 and .NET 3.0 x64 versions (if they are not already installed)
- Check in the web site properties that it is set to use ASP.NET 2.0. Sometimes for some reason, it goes blank.
Also is there any web applications running on the same IIS server in 32-bit mode? IIS x64 has a limitation where you can't mix 32-bit with 64-bit mode on the same IIS server instance. (See http://support.microsoft.com/kb/894435)
Other than that, as long as you are installing with local admin rights, I don't see why it should fail unless the IIS installation is corrupted or the server is locked down.
If this still persists, I would try to see if you can log a support ticket to get a support member to review the environment.