I might be off on this, but with the KeyStudio I think you should also have a USB Micro, and that is the hardware that Pro Tools SE is looking for in your case.
http://www.m-audio.ca/images/global/...yStudio_EN.pdf
USB Micro Audio Interface Features
Low latency performance through ASIO / CoreAudio driver architecture
1/8" mono/stereo input for instruments, microphones, and line-level devices
1/8" stereo output for headphones or powered monitors
Bus-powered through USB
Qualified audio interface for Pro Tools M-Powered and M-Powered Essential
More info:
http://www.m-audio.com/index.php?do=...25fd69470b3dc1
Joel