After migrating PA Server Monitor from Windows Server 2008R2 Windows Server 2012R2, Powershell scripts no longer work. I actually get the same error if I press Test Script when the script editor is empty.
I found this post, but it did not help - http://support.poweradmin.com/osqa/questions/578/execute-script-action-powershell-script
Powershell scripts run successfully from the command line.

Thanks Gary.