trying to add several meta boxes and when callbacks are called there is an error [closed]

Question

I am making a plugin that adds meta boxes to post. i have a function that currently defines 3 meta boxes. now when i define the callback that prints the mockup there seems to be a problem

I get the error: Warning: call_user_func(oap_price_mockup) [function.call-user-func]: First argument is expected to be a valid callback in /home1/xx/public_html/xx/wp-admin/includes/template.php on line 927

Here is my code:

    /* Add Costum Field*/
function add_custom_meta_boxes() {  

/*  Adding image meta box to post   */
add_meta_box(  
    'oap_image_box',  
    'Painting Larges Image',  
    'oap_image_mockup',  
    'post',  
    'side'  
); 

/*  Adding price meta box to post   */
add_meta_box(  
    'oap_price_box',  
    'Product Price',  
    'oap_price_mockup',  
    'post',  
    'side',
    'high'
); 

/*  Adding variation meta box to post   */
add_meta_box(  
    'oap_variation_box',  
    'Product Variation',  
    'oap_variation_mockup',  
    'post',  
    'normal',
    'high'
); 

} 
add_action('add_meta_boxes', 'add_custom_meta_boxes'); 


/* Prints the image html mockup */
function oap_image_mockup( $post ) {
wp_nonce_field( plugin_basename( __FILE__ ), 'image_price_variation' );

$productImage = get_post_meta( $post->ID, 'productFullSizeImage', true );
if($productImage){
    $html = '<div class="imageHolder"><img src="'.$productImage.'"></div>';
}else{
    $html = '';
}
$html .= '<p class="description">Upload full painting size image</p>
<input id="oap_paintingImageID" name="oap_paintingImage" value="" size="25" type="file">
';  

echo $html;  ;
}

/* Prints the price  html mockup */
function oap_price_mackup( $post ) {
$productPrice = intval( get_post_meta( $post->ID, 'productPrice', true ) );
$html  = '$ <input type="text" size="7" name="productPrice" placeholder="price" value="'.(($productPrice != '') ? $productPrice : '').'" />';    
echo $html;
}

/* Prints the price  html mockup */
function oap_variation_mockup( $post ) {
$productVariation = get_post_meta( $post->ID, 'productVariation', true );
$variation_res = oap_get_meta_table($productVariation); // ignore private fucntion that parse this string and returns a table and counter
$variationTable = $variation_res['table'];
$variationCounter = $variation_res['counter'];


$html  = $variationTable;
$html .= '<input type="hidden" id="variationCount" value="'.(($variationCounter != '') ? $variationCounter : 1).'" />';  
echo $html;
}

Thanks in advanced