It is trying to access something in your onEnter function
that doesn't exist, or an object that doesn't have a certain
property or method. Try commenting stuff out and see which of them
makes the error go away. You need to isolate the problem. I can't
say because I am not looking at the FLA. Comment out goToAndPlay.
Does it still give you that error? If so then it may be your if
clause. Comment the whole clause out and make sure there is nothing
wrong with your function. That is what I do when I try to isolate
an error. Maybe try just putting a trace in there that traces the
currentFrame to be sure you're getting that info in there....