On my own EMPEG, connecting from my Linux desktop machine (a homebrew machine), I never got the serial port quite working. Then I dragged home a laptop running Windows (a Sony Vaio) and everything worked like a champ. The Linux box is presently uploading about 10GB of music to the player via Ethernet, averaging about 380 KB/sec. Divide that out, and it should be ready to go tomorrow morning.

Moral of the story: serial ports suck, and they may well suck more on Linux than on Windows. But, you only need the serial port long enough to configure the machine and then you can do everything else via Ethernet.

P.S. Thanks Mike Crowe for helping me diagnose my problems. support@empeg.com is a wonderful thing.