上载文件PHP时偏移量类型非法

全部，我使用这个输入字段：

<input type="file" name="image_to_upload_image" accept="image/*">

然后我尝试用以下代码处理文件上传：

if ( $_FILES["image_to_upload_image"] ) { 
    echo "it will try and upload";
    $file = $_FILES["image_to_upload_image"];
    print_r($file);
    $newupload = bmt_handle_attachment_new_post($file,$post_id); 
    echo "The newupload is: ".$newupload;
    set_post_thumbnail( $post_id, $newupload );
}

它调用以下函数：

function bmt_handle_attachment_new_post($file_handler,$post_id,$set_thu=false) {
    // check to make sure its a successful upload
    if ($_FILES[$file_handler]['error'] !== UPLOAD_ERR_OK) __return_false();
    require_once(ABSPATH . "wp-admin" . '/includes/image.php');
    require_once(ABSPATH . "wp-admin" . '/includes/file.php');
    require_once(ABSPATH . "wp-admin" . '/includes/media.php');
    $attachment_id = media_handle_upload( $file_handler, $post_id );
    if ( is_wp_error( $attachment_id ) ) {
        // There was an error uploading the image.
    } else {
        // The image was uploaded successfully!
    }
     // If you want to set a featured image from your uploads. 
    return $attachment_id;
}

我正在做与此示例相同的事情：http://codex.wordpress.org/Function_Reference/media_handle_upload

为什么说偏移类型非法？

更新：我有另一个表单，除了处理多个文件上传外，它有相同的输入字段：

<input type="file" name="kv_multiple_attachments[]"  multiple="multiple" >

如果我将其传递给以下表单处理程序：

if ( $_FILES ) { 
    $files = $_FILES["kv_multiple_attachments"];
    $gallery_id = $_POST['gallery_for_upload'];  
    foreach ($files['name'] as $key => $value) {            
            if ($files['name'][$key]) { 
                $file = array( 
                    'name' => $files['name'][$key],
                    'type' => $files['type'][$key], 
                    'tmp_name' => $files['tmp_name'][$key], 
                    'error' => $files['error'][$key],
                    'size' => $files['size'][$key]
                ); 
                $_FILES = array ("kv_multiple_attachments" => $file); 
                foreach ($_FILES as $file => $array) {                          
                    $newupload = bmt_handle_attachment($file,$pid,$gallery_id); 
                        //$thumb_url = wp_get_attachment_thumb_url( $newupload );
                        //echo "<img src=".$thumb_url.">";
                }
            } 
        } 
    }

然后使用相同的处理功能：

function bmt_handle_attachment($file_handler,$post_id,$gallery_id,$set_thu=false) {
// check to make sure its a successful upload
if ($_FILES[$file_handler]['error'] !== UPLOAD_ERR_OK) __return_false();
require_once(ABSPATH . "wp-admin" . '/includes/image.php');
require_once(ABSPATH . "wp-admin" . '/includes/file.php');
require_once(ABSPATH . "wp-admin" . '/includes/media.php');
$attachment_id = media_handle_upload( $file_handler, $post_id );
update_post_meta( $attachment_id, 'bmt_gallery_id', $gallery_id );
 // If you want to set a featured image frmo your uploads. 
return $attachment_id;
}

上传的文件没有任何问题。