The empeg's ethernet chip is fried, and unfortunately it is sticking D7 on the data bus that gets shared with the drive(s) and other devices.

If you don't need the ethernet (tunes uploading??), then you could just take an exacto knife and sever that one pin from the SMC ethernet chip, and the rest would probably work.

Otherwise, major chip-replacement surgery is required on the SMC ethernet chip.

Cheers