gan newbie mau tanya ini maksud erorr bagaimana yah ?

//
// ViewController.m
// dasar
//
// Created by ivan gotama on 11/27/12.
// Copyright (c) 2012 ivan gotama. All rights reserved.
//

#import "ViewController.h"

@interface ViewController ()
{
AVAudioPlayer *avPlayer;
}

@end

@implementation ViewController

- (IBAction)sliderVolumeActionid)sender
{
UISlider *mySlider = sender;
[avPlayer setVolume:mySlider.value];
}

- (IBAction)stopButtonid)sender
{
[avPlayer stop];
[avPlayer setCurrentTime:0];
}

- (IBAction)pauseButtonid)sender
{
[avPlayer pause];
}

- (IBAction)playButtonid)sender
{
[avPlayer play];
}

-(IBAction)sayhello;
{
label.text = @"Hellow World";
}
-(IBAction)saygoodbye;
{
label.text = @"Goodbye World";

if (label.text = @"Goodbye World")
{
label2.text = @"Developed BY Ivan";
//UIImage.image=@" ";
}
}

- (void) updatemyProgress
{
float progress = [avPlayer currentTime]/[avPlayer duration];
self.myProgressView.progress = progress;
}


- (void)viewDidLoad
{
[super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.
NSString *stringPath=[[NSBundle mainBundle]pathForResource:@"untukmuselamanya" ofType:@"mp3"];
NSURL *url = [NSURL fileURLWithPath:stringPath];
NSError *erorr;

avPlayer = [[AVAudioPlayer alloc]initWithContentsOfURL:url error:&erorr;];
//[avPlayer numberOfLoops:2];
[avPlayer setNumberOfLoops:2];
[avPlayer setVolume:self->sliderVolumeOutlet.value];
//[NSTimer scheduledTimerWithTimeInterval:.1 target:self selectorupdatemyProgress) userInfo:nil repeats:YES]
//kenapa di katakan salah yah : updatemyProgress
[NSTimer scheduledTimerWithTimeInterval:.1 target:self selectorupdatemyProgress) userInfo:nil repeats:YES];
}


- (void)didReceiveMemoryWarning
{
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}

@end