When installing SCOM 2012 w/webconsole you might the this error message during installation.
The ISAPI and CGI Restrictions are disabled or missing: Web Console cannot operate properly because the ISAPI and CI Restrictions in Internet Information Services (IIS) are disabled or missing for ASP.NET 4.0.
ASP.NET 4.0 Registration Check: The ASP.NET 4.0 handler is not registered with IIS.
you must open a Command prompt as Administrator and run the following command which registers ASP.NET 4.0 with
IIS:%WINDIR%Microsoft.NETFramework64v4.0.30319aspnet_regiis.exe –r
You should receive the following output:
Start installing ASP.NET (4.0.30319) and changing IIS configuration to use this version of ASP.NET.
Finished installing ASP.NET (4.0.30319) and changing IIS configuration to use this version of ASP.NET.
Secondly, run Internet Information Services (IIS) Manager, open ISAPI and CGI Restrictions properties of the web site, select ASP.NET v4.0.30319, and then click Allow.
NOTE: ISAPI and CGI Restrictions in IIS for ASP.NET 4 are not enabled by default so this step is also applicable in case if you have installed IIS before installing .NET Framework 4.
Might be that you need to restart the setup in order for the prerequisites to register properly 