To receive answers from Samsung S2 phone you need to sign in to Google Talk.
What do you mean with that?
You ask your phone something and expect it to answer ?
If Google Talk is offline there is no way to establish a communication with my device via the web interface .
Through what web interface?
I also tried to upgrade to Hangouts but it only works for a while.
Hangouts and AT have nothing to do with eachother.
The biggest problem is that if the battery is down and I replace with a new one, i have to reconnect to Google Talk to make a connection with Google's servers
Ofcourse you need to do so or do you expect the phone to keep working without a battery?
Of course if my phone was not in my hands it would be an impossible task and avast anti theft has no utility.
AT = a utility/application
What I have to do to establish a constant communication with Google's servers to run avast anti theft ?
Nothing as it is not needed.