Installing AuthAnvil Two Factor Auth there is an error in the setup log (located at C:\Program Files\Scorpion Software\AuthAnvil Setup V5.0\AuthAnvilSetupLog.log) related to Windows Identity Foundation:
1000* 1/1/2013 12:00:00 PM ~ Installing Windows Identity Foundation caused the following error 9063* 1/1/2013 12:00:00 PM ~ RunEXEProcess() failed with exit code: 1
Windows Identity Foundation requires at least Windows Server 2008 with Service Pack 2. This error will occur when the server is only running Service Pack 1 and is not fully updated.
Windows Server 2008 is a supported operating system once it has this latest Service Pack. Update the server through Windows Updates or by manually downloading SP2.
AuthAnvil Two Factor Auth v5.0 or later on Windows Server 2008