Nah, Antivir's behaving itself. I've years of good experience of that thing, and of the three or so antivirus thingys on this comp (on top of the built-in Windows ones) it's the only one that hasn't given any trouble and, thus, has been allowed to stay (I ended up wiping ZoneAlarm due to some compatibility issues).

In another context I noticed I had two Java runtimes installed, so I cleaned away them both and reinstalled the latest version. Remains to be seen if that fixed the matter.
And if it did I'm going to feel very stupid.