Hey Jack, I hear and feel for your frustration in trying to get this P4 working with XVOD. I say this because I am a recent new customer who bought a P4 and spents weeks trying to get this XVOD setup. I too had encountered this GSM-11 error and I have spent many hours on the phone with Comcast trying to figure this out. It's really disappointing to know that when you call them to get help, but they can't help you out because they just don't know how to debug XVOD problems on a TiVo P4 unit (and yet they continue to brag about their customer guarantee BS!!). Anyway, I want to share my 2 cents worth in light of hoping you might eventually get XVOD working for you. My XVOD is working nicely now. By no means what I'm about to share is technical. Just my recent experience to get things working (at least for my case). 1) Check to make sure channel 1 (or 701) is listed in your channel lineup/listing. 2) If channel 1 is not listed, I called Comcast CableCard support directly (877-405-2298) and request them to resynchronize your CableCard with your TiVo P4 because XVOD is not working. Comcast support may claim that your zip code or address may not have XVOD available in your area. Don't believe them unless you can verify using - www dot tivo dot com / xfinity. But if this webpage replies that it does, then you have XVOD in your area. Comcast tried to pull this stunt on me but I told them otherwise. I'm sorry to hear your frustration. I hope you get your XVOD working soon.