Decompression Bomb?

I use the Home free version and got a couple of these errors on a virus scan with Avast. What is this and is it dangerous?

I think help files have some info…
Other possibility is clicking ‘Settings’ on my signature and browsing for the [Scanner] section.
There are the values you can customize for the decompression bombs.

See http://forum.avast.com/index.php?topic=15389.msg131213#msg131213