Cisco Wireless :: RV120W Firewall / Router Corrupts Data?

I just recently replaced an older linksys pre-N router with a RV 120W.  I thought this would be a good choice as a more professional router.  I installed this router last week and things seemed to be working normally for web browsing, though I was receiving more incomplete pages and broken graphics.  Yesterday, I tried to watch a youtube video a friend had sent me and it would not play.  I tried several other videos from youtube and other sources with the same result: stalled videos, partial played videos followed by a spinning wheel. It was late, so I figured something was going on with Comcast and went to sleep.  This morning, I was trying to download Anti-virus updates.  The updates failed multiple times.  I then tried some videos again with the same results.  I tried downloading .ZIP files from several sources, and while the file completely downloaded, each and every file was corrupted and unusable.  Before I called Comcast to complain about my Internet being flaky, I unplugged the Comcast Arris TM502G device from the Cisco router and plugged it directly into my computer fully expecting the problem to persist, but the problem immediately dissapeared.  The immediate evidence is that the problem lays with the Cisco Router.  It appears that I can't make any changes on the Comcast device as it has a comcast public IP address and does not seem to have any web or telnet interface to change the settings. 
 
- On the Cisco router, I disabled every non-essential service: VLAN, QOS (bandwidth profiles), IPV6, etc

- I updated the FW to the newest version the day I installed the router

- I power cycled the router

- I power cycled the comcast device
 
I need to resolve this issue as soon as possible, but I'm not sure what to try next, and I'm confused about my support options after trying to navigate Cicso's support pages.  It offers live chat, e-mail support, etc, but everything I go into requires a contract number.