Seen a lot of this since the maintenance. It seems that it is related to some regions. My advice is this. TP to someplace that voice os known to be working properly ( http://maps.secondlife.com/secondlife/Phoenix%20Firestorm%20Support/250/6/4001 works ) , disabale voice and then relog there. Once logged in wait a couple minutes for things to rez and then enable voice. That said if you can get your home region restarted that "should" also solve the problem.