Newbie trouble uploading with RBBB

Hi all,
I am having difficulty uploading my code.
I am using version 0018.
I have checked that I have selected the correct board (duemilanove 328), and have selected the USB port(usb0).
I have also tried resetting the board immediately before uploading.
I keep getting the error message:-

avrdude: stk500_getsync(): not in sync: resp=0x00
avrdude: stk500_disable(): protocol error, expect=0x14, resp=0x00

The strange thing is, that it worked the other day, so makes me think I'm doing something wrong....
Pls help!

I should add that I recently installed Ubuntu 10.04, and I was able to upload to the RBBB boards (2) a few days ago.
Both the RBBB boards are having exactly the same problem.

I just tried uploading the code to a Arduino duemilanove board, and it worked.

Any suggestions, I'm lost!

Swap chips between Duemilanove & RBBB?
You don't say what is providing USB/Serial interfacing for the RBBB. Maybe that part is bad.