Installed AIS today, did some testing and so i disabled entire AIS through tray context menu (Disable for 10 minutes). After i was done, i re-enabled it, however Security Center is now still showing that avast! Firewall is disabled, even though that’s not true. Antivirus part status is ok.
AIS final and WinXP SP3 x86.
It looks like you have to restart the system in order to get this fixed. Although Security Center thinks there are more firewalls active. But there are only AIS firewall and Windows Firewall. And Windows one is disabled.
So, the status is all messed up in Security Center as far as firewall part is concerned.
Yeah, logos noticed this too: http://forum.avast.com/index.php?topic=54057.0
doesn’t happen anymore for unknown reasons now… 
…but I got another one, the tray icon doesn’t appear very often, must log out and back in to get it back.