Please take note that a Mac version of the pak exporter (the current quick version here, as well as the fully-featured version to follow it) is going to need to accommodate Mac users across a wide expanse of operating systems as well as hardware.
This ranges from the 32-bit 10.6.8 Snow Leopard, to 64-bit Lion (post-10.7.5), and fully 64-bit operating systems Mountain Lion 10.8, Mavericks 10.9, and Yosemite 10.10. (And God-only-knows what new iteration of OS X that Apple chooses to release later this year.) Whoever is porting this pak program from Windows to Mac (or writing one as a 100% Mac-native utility?) should be mindful of this. Thank you!