In trying to recreate the error to post the message here I discovered the problem. You must use single quotes in the Where clause as opposed to double quotes or brackets. I was trying to use double quotes, when my original looked like this:

Where Lookup.FieldName = 'MSPUSERNAMV'

Doesn't work:
Where Lookup.FieldName = "MSPUSERNAMV"

Thanks for the making me think.

DJ :o)