Leopard unable to upload

Possibly my problem is the same with many others who asked for help here:

I can connect my Atmega328 Duemilanove to my MacBook and it turns up alright upon ls /dev/usb, I can choose the cu.usbserial from the Tools-menu. BUt after that all that happens is the RX LED blinking and obviously no upload taking place. Th e TX LED doesnt come on. It works fine from a Win PC with the latest Arduino software and exactly the same settings.

Did you install the FTDI drivers?

http://arduino.cc/en/Guide/MacOSX

Thanks for your reply. I did install the FTDI driver. When I plug in the Arduino it shows up alright under system profiler as FT232R-USB-UART. I experimented with different wires to no avail. When I connect the RX and TX pins I can echo output from my Mac when switcjing the Arduino software to serial monitor. When I try uploading while having those pins connected it still won't upload but give an out of sync error. Is it worth tinkering around with the driver some more in view of those facts?

What happens if you have NOTHING connected to it and upload something like a Blink LED 13 sketch?