As I had said above- I built a self-contained SDK a while ago, which I'm assuming is what you're using as I saw the string "AVR8_SDK" in your paths, and that was fairly unique for the SDK I had built a while ago (almost exclusively for PS3/AVR development).
As I've detailed above, there is no need to install TWAIN-SANE or CROSSPACK with my SDK. Everything you need to compile and download AVR firmware for the PS3 jailbreak keys is included in that package (though, usage is not limited to the PS3 jailbreak units- the SDK will work with any AVR 8-bit MCU).
As I've also detailed above, using the SDK is simply a matter of mounting the disk image and double-clicking on "SDK Terminal". Once you're done with the SDK, just close Terminal.app and unmount (eject) the disk image. It's that simple.
The SDK already contains libusb, dfu-programmer, avrdude, and a few other utilities in an easy to use package.