I'm not sure if this is related to changes made in the upgrades or not, but I'm finding on the new desktop that with the Avast Web Shield running, Sentinel is unable to connect to the webservice. I didn't figure out what was blocking Sentinel until it was already late, but every combination of dumbing down the Web Shield and adding exceptions for CIT that I could think of at the time was unable to permit Sentinel to send data through with the sheild running. Sentinel only sent data with the Web Shield stopped entirely.
Admittedly, this new computer is the first time I've actually tried out Avast, so I wouldn't go so far as to say I'm as familiar with what to tweak as in McAfee's Security Center. However, Sentinel was working (for the most part - there was still that issue with characters with custom avatars) prior to the down time without any tweaking of the Web Shield.
It might just be me, but if anyone running Avast has encountered issues with Sentinel, try turning off the Web Shield briefly and seeing if Sentinel is able send data while that's off.