last IceWM issue, tar files

how do I go about untaring files in icewm? I tried the usual linux command, but I got

tar:invalid tar magic

I havent run into any issues yet. Possibly a bad file?

tar -zxvf filename.tar.gz

tar -xjvf filename.tar.bz2

bunzip2 -d filename.bz2

tar -xvf filename.tar

Use whichever depending on the file extention.

Cheers.