I'm really sorry to hear that you were getting the error code 6117 when trying to watch On Demand on Monday. I've done a little bit of investigation, and can see that on Monday evening we were experiencing some issues with the On Demand / Catch UP TV in your area. Service should have gone back to normal later that night.
I've run some tests on your TiVo® this morning and all stats appear to be fine, and can see no further local issue.
Could you please let me know if you are still experiencing an issue with these services?