Well have you checked to see if it is compatible with the os? maybe the manufacturer has an installer. it might need udated kexts. if not you might have to try load the kexts from your previous os that worked.
Ok i took a look at http://us.focusrite.com/downloads?product=Saffire
If that's your driver, your going to have to stay in snow leopard or lion, running in arch=i386 mode to use it.
I looked at its binary file and it's not good news:
SaffireControl are: ppc i386
ML does not support 32bit