Sharepoint Foundation 2010 / failed psconfig after update to SP1

After updating SharePoint Foundation 2010 to SP1 when I run the psconfig command I get the following error:

 System.MemberAccessException.  Unable to create an instance System.Collections.Generic.Dictionary`2[Microsoft.SharePoi
nt.Administration.SPUrlZone,System.Collections.Generic.List`1[T]], because
parameter Type.ContainsGenericParameters is True.

Any thoughts?

Thanks in advance.