Well I had the old scan only with the serial connection and it worked fine which is really wierd.
My truck is a 2003 Chev Silverado SS w/ 6.0. I' m not sure of the operating system. I saw it the other day I can't remember where and I'm not connected to the truck right now though.
I haven't tried reading the tune with the tune tool yet. It's a tuned PCM from PCMforLess.