Hi,
Out of curiosity, which version of Service Center are you using when attempting to run this test? Have you tried Service Center for DOS? If so, do you experience any issues there?
One thing you could try would be acknowledging the enumeration error and then clicking on File then Refresh from the drop-down menu. This will cause the message to appear again, but should allow you to continue testing as expected. This has worked in a previous instance where this issue was seen, although the hardware configuration was different from what you are testing with.
Please let me know if the issue persists.