USB booting :: Invalid system disk (USB HDD)

Hi, I'm trying to boot DSL from a usb pendrive on a VIA EPIA ML6000. This is what I have done so far:

1) Use the DSL live cd on my regular pc to create the bootable pendrive (Apps --> Tools --> install --> USB HDD pendrive). This seems to work, so far so good.

2) My ML6000 does not have a cdrom or hardisk, so in the bios I set boot from USB HDD.

3) Plug in the pendrive and start the ML6000, the LED of the pendrive flashes, but booting fails with the message 'Invalid system disk'

What did I do wrong? And how to fix the problem?

I forgot to mentions, my pc does boot from the pendrive. So I figured it's a problem with the ML6000 and tried the USB zip instead. This works fine. I still have no idea why the hdd thing isn't working...

original here.