Navigate to C:\windows\system32\inetsrv\config\ and open the file called applicationhost.config.
Search (Ctrl+F) the file for the entry for overrideModeDefault, and change that setting to overrideModeDefault="Allow".
Open a command prompt on the server, and go to C:\WINDOWS\Microsoft.NET\Framework\v2.0.50727
Once there, issue the following command:
Then reset IIS by running the command "iisreset".
NOTE: For NetVoyant, these steps need to be performed on the NV Master and all the pollers. For SuperAgent 9.0, this also needs to be done on the collectors.
After those changes, refresh the web and the errors should clear.