change the last line to $zip->addFile($fileWithPath) != AZ_OK || die "couldn't add $fileWithPath\n";

The single quotes are preventing the variable from being interpretted. Also, the author uses the AZ_OK constants for status. . .

- - arden.

update: Of course, I meant in your code, not in your post! Also added the AZ_OK info.
update2: As discovered in the CB, you must keep your $zip variable in scope when trying to execute methods on it! :)