(im using the unarch from 3.9 dock bar to unpack it)
UnArc does not work in its first version. You need to install Boingbag 1 to correct it. You should install BB1 anyway. And BB2, too.
It has nothing to do with the version of Installer. The file in question is just not there when using UnArc. And please do not recommend Boingbags > 2.
