When you upgrade tazpkg to the cooking version the release you had set prior to the upgrade remains.You had set-release cooking thats why you were getting the errors trying to extract the cooking tazpkg with tazpkg 2.8.1.The package compression in stable wasn't changed and still works with tazpkg 2.8.1 The newer version tazpkg 3.2.1 will work both repository's and could break stable if you forget to set-release back to stable.

So be careful newbie and backup!!!

The ZliTaz I downloaded was the version on the aircrack site http://download.aircrack-ng.org/slitaz-aircrack-ng-20091124.iso now i see it are two projects merged into one and its based on the cooking version.
I thought is was the stable version and the settings in where incorrect.
I was wrong :*)

--Sax--