Disable buttons from MX to version 5 script

I have been using this script in the main timeline to disable buttons except I require my flash for flash 5, and the script no longer works, does anyone know of an alternative method for disable buttons until a desired frame?

current action script is

[AS]

MovieClip.prototype.enableButton = function() {
for (var name in this) {
if (this[name] instanceof MovieClip) {
this[name].enableButton(arguments[0]);
} else if (this[name] instanceof Button) {
this[name].enabled = arguments[0];
}
}
};
navigationBar.onEnterFrame = function() {
this._currentframe == this._totalframes ? this.enableButton(true) : this.enableButton(false);
};

[/AS]

thank you :slight_smile: