PowerGUI Error : Microsoft SharePoint is not supported with version 4.0.30319.1 of the Microsoft .Net Runtime

I’m used to work with PowerGUI script editor for developing Powershell scripts for SharePoint 2010. This time, after updating PowerGUI with version 3.2.0.2237 and running a SharePoint cmdlet, I got this error:

“Microsoft SharePoint is not supported with version 4.0.30319.1 of the Microsoft .Net Runtime."

After investigations, this issue is caused by PowerGUI itself. To fix it, open the ScriptEditor.exe.config file placed in the PowerGUI installation directory. Remove of comment this line:

Restart the script editor and everything works again !

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

I just deployed a brand new .Net 4 website in IIS on my machine and get this error:

It seems that some .Net 4 modules have not been installed properly on this machine…

I managed to fix the issue quickly by running those two commands:

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

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