I have a similar problem : avast doesn't update either automatically or manually. Avast download the file "servers.def.stamp" at 100 % on first gauge bar at 0% on the second gauge bar and freeze.
My configuration : Win 98 SE, Zone Alarm 5.0.590.043, avast 4.1.418, VPS 0426-0 (June, 22, 2004).
Please note that I have update Zone Alarm on june, 23, 2004, maybe there's a compatibily problem ? I tried to reconfigure the firewall to accept the connexion from avast but nothing has changed. I didn't uninstall and reinstall avast : I suppose it won't change anything.
Do you have any idee about the problem ? Thanks.