Help! Microphone Trouble

Hello,
I need help loading a movieclip when sound is detected.
This is my code so far…

var active_mic:Microphone = Microphone.get();
_root.attachAudio(active_mic);

if (Mic.activityLevel = 5000) {(_root.loadMovie(“Dream1.swf”))
}

First time using mic, any pointers???