At 02:15 PM 4/22/2008, you wrote:
This morning I installed the 650 build of NOD32 on two workstations.

As of right now, both of these workstations are returning the error "Virus signature database could not be updated" and give me a virus signature DB of 2945 (20080313).  Checking a worksation with build 642 has no issues updating and gives me a signature DB of 3046 (20080422).

Anyone else experiencing these symptoms?

I've been having similar issues with NOD32 today. My laptop (which is not connected to the internet when at home, and had very out of date virus signatures) was running an older build of NOD32, and failed repeatedly today when it tried updating today. I installed build 650 and it still failed to update. After doing some other things (e.g. uninstalling an old VPN and installing the newest version), I tried again later and NOD32 did finally succeed in updating the virus signatures. Meanwhile I also installed build 650 on my desktop PC, and it repeatedly fails on the update.