decompression Bomb

I have had Avast installed for several months now, It’s great. I need to better understand the files flagged as “Decompression Bombs” . Are they dangerous? Should I delete them? How should they be treated?

Thanks,

Russ

Here http://forum.avast.com/index.php?board=2;action=display;threadid=1647 you can find more info about the decompression bombs. Shortly, just a prevention of the antivirus to avoid colapse of the system when a small archive generates tons of files of very big size and try to scan them.