What does this pop-up mean?

[system]

Can someone answer these questions?

Where did this pop-up come from? How do I get rid of it? And what is it?

http://tinypic.com/r/rsvqlk/5

With kind regard,

[Pondus]

http://forum.avast.com/index.php?topic=136197.0

http://forum.avast.com/index.php?topic=136276.0