QUOTE(Caos @ 18.04.2009 09:42)

Give more info, post the logs for review, S.O., etc...
I also have this problem and here is the last log:
---- LOG (extrato) ----
[20/04/09 10:02:26 I] Update source 'http://dnl-18.geo.kaspersky.com'
[20/04/09 10:02:27 A] File 'master.xml' downloaded
[20/04/09 10:02:27 E] Wrong file signature
[20/04/09 10:02:27 E] Update 'Kaspersky Anti-Virus for Mail Servers' failed
[20/04/09 10:02:27 A] Checking new bases
[20/04/09 10:02:50 E] Update 'Kaspersky Anti-Virus for Mail Servers' failed
What definitions should I use here? (I'm in Portugal)