sprite sheet not working for retina display-Collection of common programming errors

I have create a sprite sheet for non retina display and its working fine on simulator.. I have used the code

 -(Void)addSprites{
     [[CCSpriteFrameCache sharedSpriteFrameCache] addSpriteFramesWithFile:@"image.plist"];

    CCSpriteBatchNode *spriteSheet = [CCSpriteBatchNode batchNodeWithFile:@"image.png"];
    [self addChild:spriteSheet];

 // Load up the frames of our animation
    NSMutableArray *walkAnimFrames = [NSMutableArray array];
    for(int i = 1; i < 5; i++) {
        [walkAnimFrames addObject:[[CCSpriteFrameCache sharedSpriteFrameCache] spriteFrameByName:[NSString stringWithFormat:@"image%d.png", i]]];
    }

    CCAnimation *walkAnim = [CCAnimation animationWithSpriteFrames:walkAnimFrames delay:0.20f];
// Create a sprite for our bear

    background = [CCSprite spriteWithSpriteFrameName:@"image1.png"];
    background.position = ccp(280, 175);
    self.walkAction = [CCRepeatForever actionWithAction:[CCAnimate actionWithAnimation:walkAnim]];
    [spriteSheet addChild:background];  
}
 -(void)startAnimation{
    [background runAction:_walkAction];

}

And for for device i have created sprite sheet with retina image with double size and image named like image@2x.. the created plist is myplist@2xplist and image file is [email protected]

I mean there are 4 files

for non retina display.

1) imagefile.png(sprite sheet)

2) myPlist.plist

for Retina display.

1) [email protected](sprite sheet) the plist key name for every image is also like [email protected]

2) [email protected]

but the above code is not working for this code. m i doing something wrong or missing somthing? my app crash on device with error message

 CCSpriteFrameCache: Frame 'image1.png' not found
2013-05-03 16:19:49.764  *** Terminating app due to uncaught exception 
'NSInvalidArgumentException', reason: '*** -[__NSArrayM insertObject:atIndex:]: object    cannot be nil'

but the above code is working fine on simulator