The most obvious first steps to getting the Clip working properly are as follows:
Get the Clip connected to the Mac so that it appears as a mounted drive.
You can reformat the Clip using the Disk Utility program on the Mac - use the DOS format option.
Download the latest firmware onto the Mac, decompress it and then drag it to the root directory of the Clip.
Eject the Clip using the Finder eject procedure.
Disconnect the Clip physially. It should reboot and load the new firmware.
Reload music into the MUSIC directory. With any luck it should now work properly.