Another error - Null object reference

[JWest46088]

I'm getting this error when I try to preview my code:

TypeError: Error #1009: Cannot access a property or method of a null object reference.
at therun4life_fla ::MainTimeline/frame1()

I don't know what it could be. I looked over my code several times, and I can't find anything. Maybe it isn't sticking out because I put the code in. All of this code is in the first frame. Any idea what it could be?

stop();

about_mc.buttonMode = true;
//runners_mc.buttonMode = true;
interact_mc.buttonMode = true;
newsevents_mc.buttonMode = true;
support_mc.buttonMode = true;

home_btn.addEventListener(MouseEvent.CLICK, onHomeClick);
about_mc.addEventListener(MouseEvent.ROLL_OVER, aboutOver);
about_mc.addEventListener(MouseEvent.ROLL_OUT, aboutOut);
next_btn.addEventListener(MouseEvent.CLICK, onNextClick);
prev_btn.addEventListener(MouseEvent.CLICK, onPrevClick);
interact_mc.addEventListener(MouseEvent.ROLL_OVER, interactOver);
interact_mc.addEventListener(MouseEvent.ROLL_OUT, interactOut);
newsevents_mc.addEventListener(MouseEvent.ROLL_OVER, newseventsOver);
newsevents_mc.addEventListener(MouseEvent.ROLL_OUT, newseventsOut);
support_mc.addEventListener(MouseEvent.ROLL_OVER, supportOver);
support_mc.addEventListener(MouseEvent.ROLL_OUT, supportOut);
contact_btn.addEventListener(MouseEvent.CLICK, onContactClick);
send_btn.addEventListener(MouseEvent.CLICK, submit);
supporters_btn.addEventListener(MouseEvent.CLICK, onSupportersClick);
links_btn.addEventListener(MouseEvent.CLICK, onLinksClick);
privacy_btn.addEventListener(MouseEvent.CLICK, onPrivacyClick);
faq_btn.addEventListener(MouseEvent.CLICK, onFAQClick);
				  
function onHomeClick(e:MouseEvent):void
{
	gotoAndStop("home");
}

function aboutOver(e:MouseEvent):void
{
	e.currentTarget.gotoAndPlay("over");
//	about_mc.addEventListener(MouseEvent.ROLL_OUT, aboutOut);
}

function aboutOut(e:MouseEvent):void
{
	e.currentTarget.gotoAndPlay("out");
//	about_mc.enabled = false;
//	about_mc.removeEventListener(MouseEvent.ROLL_OVER, aboutOver);
//	about_mc.removeEventListener(MouseEvent.ROLL_OUT, aboutOut);
//	var myTimer:Timer = new Timer(600,1);
//	myTimer.addEventListener(TimerEvent.TIMER, enableAbout);
//	myTimer.start();
}

//function enableAbout(e:TimerEvent):void
//{
//	about_mc.enabled = true;
//	about_mc.addEventListener(MouseEvent.ROLL_OVER, aboutOver);
//}

about_mc.dropdownAbout_mc.story_btn.addEventListener(MouseEvent.CLICK, onStoryClick);
about_mc.dropdownAbout_mc.founder_btn.addEventListener(MouseEvent.CLICK, onFounderClick);
about_mc.dropdownAbout_mc.runners_mc.addEventListener(MouseEvent.CLICK, onRunnersClick);

function onStoryClick(e:MouseEvent):void
{
	gotoAndStop("story");
}

function onFounderClick(e:MouseEvent):void
{
	gotoAndStop("founder");
}

function onRunnersClick(e:MouseEvent):void
{
	gotoAndStop("runners");
}

function onNextClick(e:MouseEvent):void
{
	gotoAndStop("jeremy");
}

function onPrevClick(e:MouseEvent):void
{
	gotoAndStop("runners");
}

function interactOver(e:MouseEvent):void
{
	e.currentTarget.gotoAndPlay("over");
//	interact_mc.addEventListener(MouseEvent.ROLL_OUT, interactOut);
}

function interactOut(e:MouseEvent):void
{
	e.currentTarget.gotoAndPlay("out");
//	interact_mc.enabled = false;
//	interact_mc.removeEventListener(MouseEvent.ROLL_OVER, interactOver);
///	interact_mc.removeEventListener(MouseEvent.ROLL_OUT, interactOut);
//	var myTimer:Timer = new Timer(600,1);
//	myTimer.addEventListener(TimerEvent.TIMER, enableInteract);
//	myTimer.start();
}

//function enableInteract(e:TimerEvent):void
//{
//	interact_mc.enabled = true;
//	interact_mc.addEventListener(MouseEvent.ROLL_OVER, interactOver);
//}

interact_mc.dropdownInteract_mc.blog_btn.addEventListener(MouseEvent.CLICK, onBlogClick);
interact_mc.dropdownInteract_mc.guestbook_btn.addEventListener(MouseEvent.CLICK, onGuestbookClick);
interact_mc.dropdownInteract_mc.messageboard_btn.addEventListener(MouseEvent.CLICK, onMessageboardClick);
interact_mc.dropdownInteract_mc.networking_btn.addEventListener(MouseEvent.CLICK, onNetworkingClick);

function onBlogClick(e:MouseEvent):void
{
	gotoAndStop("blog");
}

function onGuestbookClick(e:MouseEvent):void
{
	gotoAndStop("guestbook");
}

function onMessageboardClick(e:MouseEvent):void
{
	gotoAndStop("messageboard");
}

function onNetworkingClick(e:MouseEvent):void
{
	gotoAndStop("networking");
}

function newseventsOver(e:MouseEvent):void
{
	e.currentTarget.gotoAndPlay("over");
//	newsevents_mc.addEventListener(MouseEvent.ROLL_OUT, newseventsOut);
}

function newseventsOut(e:MouseEvent):void
{
	e.currentTarget.gotoAndPlay("out");
//	newsevents_mc.enabled = false;
//	newsevents_mc.removeEventListener(MouseEvent.ROLL_OVER, newseventsOver);
//	newsevents_mc.removeEventListener(MouseEvent.ROLL_OUT, newseventsOut);
//	var myTimer:Timer = new Timer(600,1);
//	myTimer.addEventListener(TimerEvent.TIMER, enableNewsEvents);
//	myTimer.start();
}

//function enableNewsEvents(e:TimerEvent):void
//{
//	newsevents_mc.enabled = true;
//	newsevents_mc.addEventListener(MouseEvent.ROLL_OVER, newseventsOver);
//}

newsevents_mc.dropdownNewsEvents_mc.articles_btn.addEventListener(MouseEvent.CLICK, onArticlesClick);
newsevents_mc.dropdownNewsEvents_mc.calendar_btn.addEventListener(MouseEvent.CLICK, onCalendarClick);
newsevents_mc.dropdownNewsEvents_mc.photos_btn.addEventListener(MouseEvent.CLICK, onPhotosClick);
newsevents_mc.dropdownNewsEvents_mc.video_btn.addEventListener(MouseEvent.CLICK, onVideoClick);

function onArticlesClick(e:MouseEvent):void
{
	gotoAndStop("articles");
}

function onCalendarClick(e:MouseEvent):void
{
	gotoAndStop("calendar");
}

function onPhotosClick(e:MouseEvent):void
{
	gotoAndStop("photos");
}

function onVideoClick(e:MouseEvent):void
{
	gotoAndStop("video");
}

function supportOver(e:MouseEvent):void
{
	e.currentTarget.gotoAndPlay("over");
//	support_mc.addEventListener(MouseEvent.ROLL_OUT, supportOut);
}

function supportOut(e:MouseEvent):void
{
	e.currentTarget.gotoAndPlay("out");
//	support_mc.enabled = false;
//	support_mc.removeEventListener(MouseEvent.ROLL_OVER, supportOver);
//	support_mc.removeEventListener(MouseEvent.ROLL_OUT, supportOut);
//	var myTimer:Timer = new Timer(600,1);
//	myTimer.addEventListener(TimerEvent.TIMER, enableSupport);
//	myTimer.start();
}

//function enableSupport(e:TimerEvent):void
//{
//	support_mc.enabled = true;
//	support_mc.addEventListener(MouseEvent.ROLL_OVER, supportOver);
//}

support_mc.dropdownSupport_mc.donate_btn.addEventListener(MouseEvent.CLICK, onDonateClick);
support_mc.dropdownSupport_mc.membership_btn.addEventListener(MouseEvent.CLICK, onMembershipClick);
support_mc.dropdownSupport_mc.store_btn.addEventListener(MouseEvent.CLICK, onStoreClick);
support_mc.dropdownSupport_mc.volunteer_btn.addEventListener(MouseEvent.CLICK, onVolunteerClick);

function onDonateClick(e:MouseEvent):void
{
	gotoAndStop("donate");
}

function onMembershipClick(e:MouseEvent):void
{
	gotoAndStop("membership");
}

function onStoreClick(e:MouseEvent):void
{
	gotoAndStop("store");
}

function onVolunteerClick(e:MouseEvent):void
{
	gotoAndStop("volunteer");
}

function onContactClick(e:MouseEvent):void
{
	gotoAndStop("contact");
}

function submit(e:MouseEvent):void
{
	var variables:URLVariables = new URLVariables();
	variables.fromname = name_txt.text;
	variables.fromemail = email_txt.text;
	variables.fromsubject = subject_txt.text;
	variables.frommessage = message_txt.text;
	
	var req:URLRequest = new URLRequest("contact.php");
	req.data = variables;
	req.method = URLRequestMethod.POST;
	
	var loader:URLLoader = new URLLoader();
	loader.dataFormat = URLLoaderDataFormat.VARIABLES;
	loader.addEventListener(Event.COMPLETE, sent);
	loader.addEventListener(IOErrorEvent.IO_ERROR, error);
	loader.load(req);
	status_txt.text = "Sending...";
}

function sent(e:Event):void
{
	status_txt.text = "Your email has been sent.";
	name_txt.text = "";
	email_txt.text = "";
	subject_txt.text = "";
	message_txt.text = "";
}

function error(e:IOErrorEvent):void
{
	status_txt.text = "Error - please try again later.";
}
/**
var variables:URLVariables = new URLVariables();
var req:URLRequest = new URLRequest("contact.php");
var loader:URLLoader = new URLLoader;
req.method = URLRequestMethod.POST;
req.data = variables; 
 
send_btn.addEventListener("click", submit)

function submit(e:MouseEvent):void
{ 
	variables.fromname = name_txt.text;
	variables.fromemail = email_txt.text;
	variables.fromsubject = subject_txt.text;
	variables.frommessage = message_txt.text;
	loader.load(req);
 
     //these next 4 lines are optional. I use them 
     //to clear out the textfields once the message is sent
//     firstName.text = "";
//     email.text = "";
 //    emailCT.text = "";
  //   messg.text = "";
}**/

function onSupportersClick(e:MouseEvent):void
{
	gotoAndStop("supporters");
}

function onLinksClick(e:MouseEvent):void
{
	gotoAndStop("links");
}

function onPrivacyClick(e:MouseEvent):void
{
	gotoAndStop("privacy");
}

function onFAQClick(e:MouseEvent):void
{
	gotoAndStop("faq");
}

[serdar]

Little bit of a long code to read here, so add some trace calls within your code to detect which line causes the null reference error.

Don't you see a line number in the error mesage?