Cannot access a property or method of a null object reference

1

Hi all,

Im new with AS3 and had to do some editing of others code.

I have this code

private function editNumber():Boolean {
            Console.log("editPlayer - #" + _cNumber.caption.text + ". ");
            var result:Boolean;
            var warning:String;
            var existingPlayer:PlayerData;
            if(_cName.caption.text == "")
                warning = "a name";
            if (existingPlayer.xml.name == _cName.caption.text)
                warning = "a new name";
            if (_cNumber.caption.text == "")
                warning = !warning ? "a number" : warning + " and a number";
            if (!warning) {        
                Console.log(" - has a name and number");
                if (!numberFree()) {
                    Console.log(" - is being added with number");
                    updateData();
                    result = true;
                }
            } else {
                    alert("Your player needs "+warning+" to play.", "HOLD UP!");
            }
            return result;
        }

After success compiling, it gave me a runtime error: [COLOR=Red]***Cannot access a property or method of a null object reference.
Fault, editNumber() ***[/COLOR]

which is this code:

 if (existingPlayer.xml.name == _cName.caption.text)

Can anyone help me please?

Thanks