Cant upload code on Duemilanove clone (RS232 port)

I bought a Duemilanove w/ ATMega 328 clone that comes with RS232 port instead of the USB. Once i connected it via a USB to Serial converter, i get the infamous avrdude: stk500_getsync(): not in sync: resp=0x00 error code while trying to upload Blink.

Im running windows 7 64bit edition. Tried installing all drivers i could find. The device manager actually recognizes the Prolific USB to serial comm port.

Also, Im very new to Arduino.