Has anybody had the same problem of nonfunctional call(green) and end(red) buttons in the front? No matter how I touch or swipe the buttons they do nothing, during incoming call or otherwise. And yes, the keylock is off. My N97 is retail version with v11.0.021.
Btw, interestingly the phone is quite usable even without the call/end keys. The only situation that I'd miss my red key is when closing those apps that don't have the Exit button mapped to the right softkey (eg. Web). It's frustrating to browse through the options menu to find the Exit command.
The green and red keys can be used to intiate or hang up a call. They can't be used to receive or reject a call if the phone is locked. Given the fact that the phone normally locks itself in 1 min. (can be customized), for most calls, you have to slide over the screen to unlock it to answer or reject.
If you go into 'settings' for the phone, you can set the phone to 'any-key answer'. That ways you can receive a call by pressing the 'Applications (Silver)' button on the phone.