Error during installation - downloaded tar file not expanding

[jwelmac]

During the installation an error is thrown when executing:
cordova platform add ios
Cordova gives a ohoh and says it can't find the Opentok.framework file.

I discovered this is due to the tar extraction not recognizing it as a gzip file
at line 14 in downloadiOSSDK.js
exec('tar -zxvf ./' + IosSDKVersion + '.tar.bz2', function (err, out, code) {

Removing the z solves the problem.