[quote name='scuba t']Yes because at first the red button didn't work either. I already have the explorer from guitar hero 2 bundle. I read somewhere that changing the batteries may work. I will try that next. Then try to get it replaced from Red Octane I guess.[/quote]I have the same problem, but on mine it's the blue button. At first, I was going to go through RMA hell with RedOctane, but a friend told me to try something and it worked for me.
If you're looking at the guitar from the front, seeing the buttons and everything in front of you, does the neck wiggle from side-to-side, slightly? If it does, try moving it like that while the game's running, usually before a song starts. Hold down the button and see if that effects it at all. In my case, it'd make the button flicker between working and not working. I shoved a tiny piece of paper towel in between the neck and the body while sliding it into place, right next to the d-pad and guide button. You only need a tiny amount, a small corner will be just fine. All you need is enough to keep it from wiggling out of place. It may differ on your guitar, or just plain not work at all, but since doing it, mine plays perfectly.
Let me know if you have any luck or need any more clarification.