which version of ubuntu are you running?Which arduino board and arduino software version? Uno requires at least arduino software version 0021.
I think that I need to use ttyUSB0 port
QuoteI think that I need to use ttyUSB0 portYou are correct. /dev/ttyUSB? If the duemilanove has powerFirst thing I would do is try a different usb cable. Then I would try running the arduino software as root (sudo arduino).If running as root works: run the command "id" to ensure to you are a member of the dialout group. Add your user id to /etc/group if requiredIf running as root did not work (with the duemilanove plugged into the usb port): execute the command "dmesg". look for a entry that looks like, "FTDI USB Serial Device converter now attached to ttyUSB0" execute the command "lsusb", look for the entry, "Future Technology Devices International, Ltd FT232 USB-Serial (UART) IC"Post the output of these command.