Did you check that your camera actually has power? We were stuck for a while because we didn't know you had to hook up the main battery and the pwm out ports were not giving any juice. The camera have led's to tell that it's on. Also, you might want to make sure that your ttl port is disconnected. The ttl and the serial are mutually exclusive (You can only plug in one or the other). Lastly, make sure you have the right serial port...Go right click on my computer, properties, hardware, device manager. Then go to the expandable tree for serial devices or sumthin and check that you have the right COM port.
Unfortunately i know all this from experience
