Here is a link from a past forum to download the new software.
And here is the direct link to download the software :
PC users: http://download.kobobooks.com/desktop/58/KoboSetup.exe
MAC users: http://download.kobobooks.com/desktop/58/KoboSetup.dmg
If it still doesn't work, you might want to give a try to Zoran's way, and try to find the libusb0.dll and replace it at the right place.