This means avast can not unpack the file (it’s a windows installer) and the reason is, you are using an
obsolete avast version. The latest avast! for linux (http://forum.avast.com/index.php?topic=145973.0)
can unpack the file without problems and has much better scan capabilities (equivalent with the latest avast!
for windows products) than the 7 years old version you are using.

The numbers should be what they are called, but there is obviously a bug there. As already said, use the latest avast version.