This just started happening to me in the last two weeks (week of November 6, 2011). None of the so-called solutions or updates found in the other threads discussing this issue work to solve this problem.
Very frustrated with this!
I had this problem 3 years ago and never got it fixed. Rebooting doesn't work and a verizon phone tech tried different fixes, but none of those worked either. I ended up just getting rid of it and getting another set top box. I'm paying more a month, but at least I don't have that annoying pop up anymore.