Differences with playing swf in IE and Firefox?

I’m finishing up my project /i appreciate your input guys - you’ve helped me a lot.
Yet, i’m experiencing werid problem - in IE the sound plays at the moment i click the MC and in Firefox there is a 1sec delay. Where’s the catch?

Here is the scripting… without this global control it’s also not working well. The switchON is attached with NewSound few lines earlier.

Wl.onPress = function() {
globalcontrol = new Sound();
switchON.start (0,1);
_global.Dzwiek = Wl;