Do you have it set that the mute button actually locks rotation instead of being used for mute? In the general settings screen, look for a setting that says: "use side switch to lock rotation / mute". You probably have yours set to lock rotation. Take a look.
True. The mute function is not reliable for me, either. The volume rocker works OK though. Since it's otherwise useless, I assigned the switch to lock rotation.
milliHelen: amount of beauty required to launch one ship.