Oh yeah that old guy. Error as old as cgminer running USB devices. From the Compac/2Pac support thread:
Q. How to get past "USB init, open device failed" ... "you don't have privilege to access" error.
cd ~/git/vthoang/cgminer/
sudo usermod -G plugdev -a `whoami`
sudo cp 01-cgminer.rules /etc/udev/rules.d/
sudo reboot
You'll want to cd into the correct cgminer folder, but that is probably obvious. Either that, or run cgminer as root.