thanks to dfergie, I found this part of the forums (I am a E* HD narcissist).
In any event, on my 622, it locked up shortly after Tripp got on board the alien wessel (read as Chekov). If I forcefully fastforwarded, it came back (well, no audio for about another 10 minutes).
I was flipping back and forth between SD and HD channels at the time (which is not unusual for me), and didn't see any other problems.
A E*/622 prob? Or a bigger conspiracy against Enterprise...you be the judge.
Must have been transmitted that way as I had exactly the same problem with my 622 recorded program.