MDT 2012 - U1 on Win8: "Please install PowerShell..."

I built a new Windows 8 machine and then installed MDT 2012-U1 and the Windows 8 ADK.  All of these are the final RTM releases and not betas or release candidates.

When I start MDT I get the error:

“Initialization Error PowerShell is required to use the Deployment Workbench.  Please install PowerShell then relaunch Deployment Workbench.”

I've tried reinstalling MDT and uninstalling the ADK but I still get the error.

I've uninstalled both and then installed just MDT by itself but still get the error.