unlink() doesn't delete the file!

Hi,
I’m using this code in my plugin to add an extra field to the user profiles so that the user can upload an image. It uploads the file perfectly but the only problem is the part that has to delete the previous uploaded image doesn’t work.

This is my code:

<?php
add_action( 'show_user_profile', 'my_show_extra_profile_fields' );
add_action( 'edit_user_profile', 'my_show_extra_profile_fields' );

function my_show_extra_profile_fields( $user ) {
?>
<script type="text/javascript">
    var form = document.getElementById('your-profile');
    form.encoding = "multipart/form-data";
    form.setAttribute('enctype', 'multipart/form-data');
</script>
<table class="form-table">
    <tr>
        <th><label for="profile_photo">Upload your profile photo</label></th>
        <td>
        <p>
            <input type="file" name="profile_photo" id="profile_photo" />
            <input type="hidden" name="action" value="save">
            <input type="submit" name="submitprofilephoto" id="submitprofilephoto" class="button" value="بارگذاری">
        </p>
            <span class="description">
            <?php
            $author_profile_photo = get_author_profile_photo($user->ID);
            if(is_array($author_profile_photo)):
            ?>
                <a href="<?php echo $author_profile_photo["url"];?>" target="_blank">
                    <img src="<?php echo $author_profile_photo["file"];?>" height="100" width="100" />
                </a>
            <?php
            endif;
            ?>
            </span>
        </td>
    </tr>
</table>

<?php
}

function get_author_profile_photo($user_ID) {

$author_data = get_the_author_meta( 'profile_photo', $user_ID );
$uploads = wp_upload_dir();
$author_data["file"] = $uploads["baseurl"] . $author_data["file"];
return $author_data;
}

add_action( 'personal_options_update', 'my_save_extra_profile_fields' );
add_action( 'edit_user_profile_update', 'my_save_extra_profile_fields' );

function my_save_extra_profile_fields( $user_id ) {

if ( !current_user_can( 'edit_user', $user_id ) )
    return false;

$upload=$_FILES['profile_photo'];
$uploads = wp_upload_dir();
if(isset($_POST) && $_POST['submitprofilephoto']!='') {
    if ($upload['tmp_name'] && file_is_displayable_image( $upload['tmp_name'] )) {

            // handle the uploaded file
            $overrides = array('test_form' => false);
            $file=wp_handle_upload($upload, $overrides);
            $file["file"] = $uploads["subdir"]."/".basename($file["url"]);

            // Setup the array of supported file types. In this case, it's just Images.
            $supported_types = array( 'image/jpeg', 'image/pjpeg', 'image/png' );  

            // Get the file type of the upload
            $arr_file_type = wp_check_filetype(basename($upload['name']));
            $uploaded_type = $arr_file_type['type'];  

            // Check if the type is supported. If not, throw an error.
            if( $file && in_array($uploaded_type, $supported_types) ) {
                if($upload['size'] > 204800) {
                     wp_die('<strong>ERROR</strong>: Maximum size allowed is 200KB.');
                }

                //remove previous uploaded file
                $author_profile_photo = get_author_profile_photo($user_id);
                @unlink($author_profile_photo["file"]);
                // I even tried unlink without the @ and it still doesn't delete the file!

                update_user_meta( $user_id, 'profile_photo', $file );

        } else wp_die('<strong>ERROR</strong>: Allowd image formats are JPEG, JPG and PNG.');

    } elseif (!file_is_displayable_image( $upload['tmp_name'] )) wp_die('<strong>ERROR</strong>: The file you selected is not an image!');
}
}
?>

Where or what is the problem?
Regards!