Please try one thing:
on one of such machines, go to the reg key
HKLM\Software\ALWIL Software\Avast\4.0\SS
and DELETE the value ClientsListenPortAddress.
Then restart the service "avast! NetAgent", and see if the same entry is logged (if there's a similar entry logged, note the address - is it still 192.168.10.2:0? The zero confuses me).
Thanks
Vlk