IIS 8.5 Cannot set App Pool Identity

I have a virgin install of IIS 8.5 and I'm trying to recreate our IIS 7 configurations.

I created an app pool and need to set the identity to a domain account.  The domain account is a member of the IIS_IUSRS and local Admin groups.

I ran the aspnet_regiis -ga admin\svc_webapptst command for both .NET 2 and 4 in both 32 and 64 bit.

I keep getting the error: The value does not fall within the expected range.

Any thoughts before I end up calling MS support and wasting $$?

Thanks

Ron