Hi. I'm new here. Wish I had found you a few days ago, but I spent several hours on hold and with two levels of DirecTV tech support today trying to nail down the same problem. (We began receiving error messages a few hours after that upgrade came down the pike Tuesday, and even after repeated reboots, we are plagued by occasional, fleeting dropouts of service.)
The first level of tech support knew nothing, but at least bucked me up to a higher level. There, I finally was told this: They said a software glitch, still unidentified, is the root cause and is widely affecting Samsung HD receivers. They are sending me a new HD receiver by FedEx at no charge, offered to dispatch a tech if necessary, and offered me a rebate for lost service.
Apparently, this problem is now widespread and a policy is in place to deal with it, though you have to struggle mightily to learn of this.