Using global property transfert with command line

Thanks very much for that. Definite newbie here.
The next issue I can't fathom following from this is an error while running TestRunner that says "Cannot invoke method plus() on null object."
I can't understand this one as the test case works ok when just running it, and I am just asking that this be done from the command line with setting the project property barcode=xxx. I have even tried it without setting this property and just using a number and the same error occurs

Joe