LOL? Are they contracting Comcast support out to Nigeria these days?
Kidding aside, everything is done over IP these days, so sure, it's remotely possible that they can see something trying to be sketchy through a DVR, but this is where the luls start: "a CSRSS.exe virus that was interfering with the signal". Okay. There is no way that any virus can somehow modify your db levels to interfere with the signal. That's just silliness. That's like viruses jumping from computer to computer through BIOS only using wi-fi. It's snake oil.
CSRSS is the user-level part of the win32 subsystem. It's not a virus. It can be infected, sure, but the solution to this is not a firewall, it's to reinstall the system. Once CSRSS is infected, you are pretty much screwed. So, go find yourself a decent bootable virus scan CD (Hiren's can do it, I think), scan the system, and if you find nothing, this is someone trying to make money on the side.
All of that said, some traffic
heresuggests that this is Comcast setting a no-record bit where they shouldn't be, and if that's the case, there is very little you can reasonably do about it (and your grandpa wouldn't want to be fucking with this, I'm sure).
Edit: More similar traffic
here. Looks like Comcast may just be fucking everyone over, which shouldn't really be all that surprising.