M-audio Audiophile Usb & Os 9.2 Options

[estiv]

I'm trying to get Pro Tools Free to work on a Blue & White Mac G3 with OS 9.2, using an M-Audio Audiophile USB interface. But I can't get it to work. I can only get a very low-level audio signal to come in and no MIDI at all.
I have tested the M-Audio Audiophile USB interface on my PC just to see if it works, and it does--both audio and MIDI signals come through to the computer. So it's not the interface. I have also tried both USB ports on the Mac, and the keyboard/mouse works on both, but the Audiophile does not work on either one. So the Mac's USB ports seem to be okay.
I have gotten the latest versions of the drivers from the M-Audio website, but they make no difference.
I'm at a loss. If there were no audio signal getting through at all that would make more sense to me than getting a very low-level signal, which is what it's doing.
Any suggestions?
TIA,
estiv