As a lst ditch effort last night I rebooted my firewall server and no joy.. still had the problem...
To try to determine if this was a firewall issue (even though all the sniffing I was doing did not indicate it was) I did this:
1) Changed my NIC default gateway to use a gateway address that bypasses the ISA firewall. I have a secondary egress router that routs around things for a few devices that I have that I can't get to go through the ISA server (IE: Playstation, TiVO, etc..)
2) Disabled the ISA firewall client.
3) Ran a connection test and is PASSED!
OK, so then I started to think this was my firewall all of a sudden. I was able to run an update and get Avast to update all it files. I then rebooted.
I figured that if I had to do this once in a while I could live with it. I put my setting back tot he way they were and just for a heck of it I ran another test. It FAILED!
I went to bed feeling beat...
This morning I woke up and checked the windows event log before coming into work. It updated on its own at roughly 6am this morning!
I am going to run a few more tests when I get home today but so far this looks promising.