I followed your instructions, and I got all the way to the end, but when I did 'make kernel-build' it ended with this:
drivers/built-in.o: In function `archos_dpm_suspend':
/home/zyntax/archos/gen8-gpl-froyo/linux/drivers/usb/storage/archos_hdd.c:261: undefined reference to `usbsata_power'
make: *** [.tmp_vmlinux1] Error 1
make: *** [sub-make] Error 2
make: Leaving directory `/home/zyntax/archos/gen8-gpl-froyo/linux'
make: *** [/home/zyntax/archos/gen8-gpl-froyo/buildroot//linux/arch/arm/boot/zImage] Error 2
make: Leaving directory `/home/zyntax/archos/gen8-gpl-froyo/buildroot'
make: *** [kernel-build] Error 2
This is on a fresh install of Ubuntu 10.10 32-bit in Virtualbox. I installed it, updated the OS, then started your steps. Not sure if this is normal and I'm holding off on the last step. I did do one extra step: in 'make kernal-config' I deselected all the Archos boards under System Type except for the A101IT since that's what I have.