Sorry for bringing this up from the dead.. But I just wanted to let y'all know, that I bought my PZ77U in 2007 and today I got the 7 blink of death. I called panasonic, and they will be sending someone out (in a week).
I highly recommend anyone finding this thread by googling TNPA4251, or TH-42PZ77U to give Panasonic a call. They seem to be quite willing to work with you.
BTW. I did _NOT_ have the upgraded firmware, which was released in 2008.