Could it be that the "Rboard" doesn't implement auto-reset? If so you'd have to do a manual reset to initiate the upload.
Select Tools->Serial Port-> port 7
Select Tools->Board->"Arduino Duemilanove w/ ATmega328"
Click on the Upload button of the sketch to be uploaded.
When the TX/RX lights flicker on the "Arduino", press the Reset button briefly. If the Rboard doesn't have RX or TX lights, press the Reset briefly when you see the "Binary sketch size:" message.