Internal Server Error 500.21 PageHandlerFactory

Just installed latest version of FileVist for the first time on W2008R2.  IIS is installed with v6 compatibility, ASP.NET, .NetFramework 4.  Upon opening the site for the first time I get the following error:

HTTP Error 500.21 - Internal Server Error
Handler "PageHandlerFactory-Integrated" has a bad module "ManagedPipelineHandler" in its module list

Can anyone help?

Thanks!

This means .NET installation is not configured on IIS properly. To fix it run this command:

%windir%\Microsoft.NET\Framework64\v4.0.30319\aspnet_regiis.exe -i

For 32-bit systems:

%windir%\Microsoft.NET\Framework\v4.0.21006\aspnet_regiis.exe -i

That worked, thanks!