API: Problems creating virtual machines with a non-admin user

I am running in to a problem using the REST API as a non-admin user.  The user has been granted the VmCreator and DiskCreator roles at the system level but when I try to create a virtual machine I receive the error "query execution failed due to insufficient permissions".  I am running RHEV 3.1.0-50 and this is a brand new install.  I can successfully create a virtual machine if I assign the superuser role to the user but I know in past installations of RHEV I have been able to create virtual machines with just the VmCreator role assigned.

I'm following the steps outlined here: https://access.redhat.com/knowledge/docs/en-US/Red_Hat_Enterprise_Virtualization/3.1/html/Developer_Guide/sect-REST_API_Guide-Example-Create_VM.html

As a side note, I am able to successfully create floating disks with this same user account following the steps here: https://access.redhat.com/knowledge/docs/en-US/Red_Hat_Enterprise_Virtualization/3.1/html/Developer_Guide/chap-REST_API_Guide-Floating_Disks.html

I see the following in /var/log/ovirt-engine/server.log when trying to create a virtual machine:

2013-03-22 06:30:17,486 WARN  [org.jboss.resteasy.core.SynchronousDispatcher] (ajp-/127.0.0.1:8702-4) failed to execute: org.
ovirt.engine.api.restapi.resource.BaseBackendResource$WebFaultException