2 same errors in one script - actionscript-3

Question

I have 2 errors:
TypeError: Error #1009: Cannot access a property or method of a null
object reference. at
BlowfishPong_fla::MainTimeline/countTime()[BlowfishPong_fla.MainTimeline::frame79:75]
TypeError: Error #1009: Cannot access a property or method of a null
object reference. at
BlowfishPong_fla::MainTimeline/airScore()[BlowfishPong_fla.MainTimeline::frame79:131]
Look at this code:
timedScore = 0;
var goalScore: int = Math.floor(Math.random() * 101) + 20;
var speedSeconds = 0;
var speedMinutes = 0;
keyNum = 0;
var OxygenTime = 0;
var OxygenMaxTime = 5;
var goalKey: int = Math.floor(Math.random() * 10) + 3;
var ballSpeedXTimed: int = -3;
var ballSpeedYTimed: int = -2;
var cpuPaddleSpeedTimed: int = 3;
stopwatch.play();
oxygenGauge.stop();
var FiftyTimed: Boolean = false;
var plzStopTimed: Boolean = false;
helpContent_Timed.visible = false;
stopwatch.addEventListener(Event.ENTER_FRAME, countTime);
oxygenGauge.addEventListener(Event.ENTER_FRAME, airScore);
goalScore_txt.text = String(goalScore);
timedScore_txt.text = timedScore;
key_txt.text = keyNum + "/" + goalKey;
stage.addEventListener(Event.ENTER_FRAME, loopTimed);
function updateTextFieldsTimed(): void {
goalScore_txt.text = String(goalScore);
timedScore_txt.text = timedScore;
key_txt.text = keyNum + "/" + goalKey;
}
function calculateBallAngleTimed(paddleY: Number, ballY: Number): Number {
var ySpeed: Number = 5 * ((ballY - paddleY) / 25);
return ySpeed;
}
function countTime(e: Event): void {
if (stopwatch.currentFrame == 61) {
speedSeconds++;
if (speedSeconds > 59) {
speedSeconds = 0;
speedtimerSec_txt.text = "0" + speedSeconds;
speedMinutes++;
if (speedMinutes > 10) {
speedtimerMin_txt.text = "" + speedMinutes;
} else {
speedtimerMin_txt.text = "0" + speedMinutes;
}
if (speedMinutes > 59) {
stopwatch.stop();
gotoAndPlay("gameover_Timed");
}
} else {
if (speedSeconds >= 10) {
speedtimerSec_txt.text = "" + speedSeconds;
} else {
speedtimerSec_txt.text = "0" + speedSeconds;
}
}
}
}
function airScore(timedScore): void {
if (timedScore == 50 && FiftyTimed == false) {
character_TiedUp.gotoAndStop(2);
FiftyTimed = true;
oxygenGauge.play();
OxygenTime++;
} else if (timedScore == 150 && FiftyTimed == false) {
character_TiedUp.gotoAndStop(2);
FiftyTimed = true;
oxygenGauge.play();
oxygenGauge.frameRate = 1.5;
OxygenTime++;
} else if (timedScore == 300 && FiftyTimed == false) {
character_TiedUp.gotoAndStop(2);
FiftyTimed = true;
oxygenGauge.play();
OxygenTime++;
} else if (timedScore == 450 && FiftyTimed == false) {
character_TiedUp.gotoAndStop(2);
FiftyTimed = true;
oxygenGauge.play();
OxygenTime++;
} else if (timedScore == 600 && FiftyTimed == false) {
character_TiedUp.gotoAndStop(2);
FiftyTimed = true;
oxygenGauge.play();
OxygenTime++;
}
if (oxygenGauge.currentFrame == 505) {
character_TiedUp.gotoAndStop(3);
oxygenGauge.stop();
oxygenGauge.gotoAndStop(1);
}
}
function loopTimed(event: Event): void {
if (plzStopTimed == false) {
playerPaddle.y = mouseY;
keyPong.x += ballSpeedXTimed;
keyPong.y += ballSpeedYTimed;
//check left and right boundaries
if (keyPong.x <= keyPong.width / 2) {
keyPong.x = keyPong.width / 2;
ballSpeedXTimed *= -1;
keyNum++;
BingTimed.play();
if (goalKey == keyNum) {
key_txt.textColor = 0x00FF00;
}
updateTextFieldsTimed();
} else if (keyPong.x >= stage.stageWidth - keyPong.width / 2) {
keyPong.x = stage.stageWidth - keyPong.width / 2;
ballSpeedXTimed *= -1;
BingTimed.play();
if (keyNum > 0) {
keyNum--;
}
if(goalKey < keyNum) {
key_txt.textColor = 0xFFFFFF;
}
updateTextFieldsTimed();
}
if (keyPong.y <= keyPong.height / 2) {
keyPong.y = keyPong.height / 2;
ballSpeedYTimed *= -1;
gameBounceTimed.play();
} else if (keyPong.y >= stage.stageHeight - keyPong.height / 2) {
keyPong.y = stage.stageHeight - keyPong.height / 2;
ballSpeedYTimed *= -1;
gameBounceTimed.play();
}
if (cpuPaddle.y < keyPong.y - 10) {
cpuPaddle.y += cpuPaddleSpeedTimed;
} else if (cpuPaddle.y > keyPong.y + 10) {
cpuPaddle.y -= cpuPaddleSpeedTimed;
}
if (playerPaddle.y - playerPaddle.height / 4 < 0) {
playerPaddle.y = playerPaddle.height / 4;
} else if (playerPaddle.y + playerPaddle.height / 4 > stage.stageHeight) {
playerPaddle.y = stage.stageHeight - playerPaddle.height / 4;
}
if (playerPaddle.paddle.hitTestObject(keyPong) == true) {
if (ballSpeedXTimed > 0) {
ballSpeedXTimed *= -1;
ballSpeedYTimed = calculateBallAngleTimed(playerPaddle.y, keyPong.y);
timedScore++
gameHitTimed.play();
airScore(timedScore);
if (goalKey == keyNum) {
if (goalScore == timedScore) {
stage.removeEventListener(Event.ENTER_FRAME, loopTimed);
gotoAndStop("gameover_Timed");
return;
}
}
updateTextFieldsTimed();
}
} else if (cpuPaddle.paddle.hitTestObject(keyPong) == true) {
if (ballSpeedXTimed < 0) {
ballSpeedXTimed *= -1;
ballSpeedYTimed = calculateBallAngleTimed(cpuPaddle.y, keyPong.y);
timedScore++;
gameHitTimed.play();
airScore(timedScore);
if (goalKey == keyNum) {
if (goalScore == timedScore) {
stage.removeEventListener(Event.ENTER_FRAME, loopTimed);
gotoAndStop("gameover_Timed");
return;
}
}
updateTextFieldsTimed();
}
}
}
}
Can anyone how to fix these?