Where am i making mistake?

1

Hi friends,
I got stuck… please help.

on (release)

{
    //THIS WORKS PERFECTLY FINE
    if (_parent.button2!= "s1")
    {
        _parent.button2 = "s1";
       this.gotoAndPlay("s1");
    } // end if
    
    
    
//THIS DOESN'T WORK: WHERE AM I MAKING MISTAKE?    
if (_parent.button1 != "s1")
    {
        _parent.button1 = "s1";
       _parent.button1.gotoAndPlay("s1");
    } // end if
    
    
    
    
}