Not saying that you DONT/ARENT having an issue.
BUT.. there are many people who ARE using the CGN3, and it works without fail.
So the modem does work. At least mostly.
That being said.. it could still be an issue with say the firmware, which is having issues with some piece of hardware specifically (which does work fine say with other hardware).
The 10/100 bug which Datalink mentioned for example..
Heard a few instanced with Realtek even gigabit cards having issues when direct connecting.