Have you put a breakpoint on your fail point in your test and then examined what comes back from your database query?
The reason I ask is that you're variable is a DB Table type... but "Keys" expects a string. I'm not sure there's a "clean" conversion of one to the other. You might need to do more work to pull the specific value out of the DB Table variable before you pass it to your "Keys" parameter. Try using the "aqConvert.VarToStr" code command in your value field to convert the DB Table value (which, from your query, should contain only a single string) to a string value and see if that works.
