Have (or did) you another Anti-Virus installed in this system, if so what was it and how did you get rid of it ?
What is your operating system and firewall ?
Try a repair of avast:
XP - Add Remove programs, select 'avast! Anti-Virus,' click the Change/Remove button and scroll down to Repair, click next and follow.
Vista, win7 - Control Panel, Programs & Features, uninstall a program, select 'avast! Anti-Virus,' click the Change/Remove button and scroll down to Repair, click next and follow.
You may need to reboot after the repair. This has in the past resolved this out of sync issue between reported and actual VPS version.