I had to change the code actually as I am now using radio buttons. Here is the code I am using:

Code:
btnSubmit.onPress = function() { 
	if(radioButtonPressed==1){
		Yes_cover_mc._visible = false;
	} 	if(radioButtonPressed==2){ 
		No_cover_mc._visible = false;
	} 	if(radioButtonPressed==3){ 
		No_cover_mc._visible = false;
	} 	if(radioButtonPressed==4){ 
		No_cover_mc._visible = false;
	}
	
	cbSpain.onPress = function() {
		radioButtonPressed=1;
	}
	cbNorway.onPress = function() {
		radioButtonPressed=2;
	}
	cbMacedonia.onPress = function() {
		radioButtonPressed=3;
	}
	cbItaly.onPress = function() {
		radioButtonPressed=4;
}
}
Unfortunately this still doesn't work even though it doesn't provide any errors. Any ideas?