There must be something else :-
If data do not pass, maybe a firewall issue…
I cannot understand ‘freeze’. What freezes? avast or the computer?
Attempting to connect and update cannot freeze a normal system…
If you want to delay the attempt to update some seconds after the connection were established, try to see here: http://forum.avast.com/index.php?board=2;action=display;threadid=1647
Does ping ‘passes through’?