this is just so add my two cents to the discussion...
I have got an Arduino Ethernet board (http://arduino.cc/en/Main/ArduinoBoardEthernet
) and a DFRobot FTDI Basic Breakout 3.3/5VR USB-2-Serial adapter (http://www.dfrobot.com/index.php?route=product/product&filter_name=FTDI&product_id=147
I tried to program it using Windows 7 64bit. I downloaded the Arduino IDE from the website. When I plugged the USB-2-Serial adapter into one of the USB ports, Windows 7 installed automatically the driver (I checked they are the latest ones: 2.08.14).
When I tried to upload a sketch into the Arduino Ethernet board, I got the message of death: "avrdude: stk500_getsync(): not in sync: resp=0x00" and nothing else. I had no way to successfully upload any sketch.
I tried everything (changing baud rate, programmer, protocol, board.txt, programmers.txt, etc.) in every reasonable combination. But nothing!
At the end I was going to surrend. Even because I read this thread declaring that the problem is in the Arduino Ethernet bootloader and it is needed another Arduino board to solve all the issues. But what if I do not have another Arduino board?!?!
Fortunately, I did another try.
I have a Linux (Ubuntu 10.04 distro) installed in a 32bit PC. I installed the linux version of the Arduino IDE. I plugged in the FTDI adapter and... magically linux installed automatically the driver. I opened the Arduino IDE, selected the corret serial port and board (arduino ethernet) and it works!!! I'm now able to upload whatever sketch I like into the Arduino Ethernet, in a reliable and replicable manner.
IT SIMPLY WORKS!!!
If it works changing the host machine (from a Windows 7 64bit notebook to Linux 32bit desktop) it means that the Arduino Ethernet bootloader, theoretically, has nothing wrong...
So man, or I'm a lucky guy or something is wrong with the Windows7 64bit implementation of (1) the FTDI USB-2-Serial driver or (2) the Java-based Arduino IDE...
I guess that the Arduino IDE is OS independent. Thus the problem is, most reasonably, on the USB-2-Serial driver that is not resilient enough to work with the current Arduino Ethernet bootloader settings.
I'm not an an Arduino expert, thus I leave to others the possibility to provide a logical explaination of what happened to me.