M-Audio Keyboard 49e on iMax computer

I have an M-Audio Keyboard 49e, and it works perferctly on my iMac, with Mac OS 10.4 operating system.

I have attempted to load the software onto my Motorola iMax apple compatible computer which has an OS 9.1 operating system. The iMax doesn't have a built-in USB bus, but utilizes an after market USB with a plug-in USB card and an extension for the mouse. The software loads ok, and the M-Audio Keyboard 49e power light comes on, but I get no sound out of the keyboard.

Does the M-Audio Keyboard 49e require a built-in USB? If not, how can I get the M-Audio Keyboard 49e to work with my iMax?