After installing VmWare Server on 64-bit Windows 2003 Server R2, I was unable to access VmWare Server's web admin page due to Service Unavailable error. VmWare support forum suggests to remove .NET Framework 2.0, which seems to help some people, but I fixed the problem by repairing .NET Framework 2.0 installation after VmWare server was installed. To do that go to Control Panel -> Add/Remove Programs, select .NET Framework and hit Change/Remove button. In the dialog select repair and let it run. After that both Default Web site and VmWare web site were running fine.