I’m not familiar with the server edition, but in my about box it says “avast! version 4.5 professional” right at the top of the info. I guess (don’t take my word for it) something simulair should show up in your about box.

Looking at your problem and my experience with other versions of avast than the server edition, I would say try a repair of Avast. (start > control panel > add/remove > Avast > change/delete > repair)

But as I said, I am not familiar with the server edition so I advise you to wait for one of the Alwil team members to respond here and from there on follow their instructions/suggestions.