I found an interesting thing. When working on my skin that I am trying to create I found that my Xbox would lock up when trying to launch an app or game.
I used the Skinny Skinner to do the skin, something in that are different then most of the other skins I have seen, the code.
I rewrote the XML by hand and it still locked up, I made the menu and stuff like all the other ones not done with Skinny too.
I found that when I used the ChipID in a text field I could no longer run any apps or games, it would just freeze. I toook that one line out of my skin and everything seems to be working ok. I then took the original file from the Skinny app and removed that ChipID like, well it worked fine there too, no more locking up, at least so far and I have rebooted and ran apps/games about 10 or more times.
Once in a while I still get that Bad skin message, but not as often.