Slitherine

I've had Avast as virus protection for a long time and been very satisfied with it.
Today I got a surprise. Played one game and nothing unusual. About an hour later I sat down to play again.
This is what I got when I started FOG:

Well, I didn't heed the warning and opened FOG the normal way.
Nothing has happened (as far as I know) but what could be the explanation for a message like that?

Gday Hidde i got a similar message yesterday i clicked on the x to get rid of it and dont seem to have any illeffects.I think it popped up when i opened up the slitherine site.

Its these over zealous virus checkers. I wish we could stop them but we cant

Thanks for replying. Was as I suspected.
Took me by surprise though, as I don't think I have ever seen that message before.
Neither with FOG nor any other program.
Must be the prevalence...FOG's an aquired taste, not for the masses to enjoy