How can I fix attachment upload error in custom addon

[lsxforo]

Hello,

While I dare try to code mine custom addon I have to request your help.
Please understand this is my first addon and I am new a bit.

I looked at some addon for attachment handling, and I try to add it to my class too.

In my case, there is output that contains "403 error" in console.log when attach button was loaded.

I have created some method at these classes;

_ControllerPublic
_AttachmentHandler
_Model
_DataWriter

and I used default attachment editor templates.

console.log error shows;

Queued file images12.jpg (45658 bytes). attachment_editor.js:13:560
XenForo.activate(%o) [object Object] xenforo.js:220
Attachments changed, total files: 1, images: 1 attachment_editor.js:13:30
Uploading images12.jpg attachment_editor.js:14:2
POST
XHR
http://localhost/happyhome/attachments/do-upload.json [HTTP/1.1 403 Forbidden 78ms]
Uploaded 45658/45658 bytes. attachment_editor.js:15:38
Object { code: -200, message: "HTTP 오류", file: Object, response: "{"error":["You do not have permissi…", status: 403, responseHeaders: "Date: Tue, 16 Feb 2016 08:17:45 GMT…" } attachment_editor.js:16:2
AttachmentUploadError:  Object { type: "AttachmentUploadError", timeStamp: 1455610665797, jQuery111009262114111006796: true, file: Object, errorCode: -200, message: "HTTP 오류", ajaxData: Object, swfUpload: null, plupload: Object, isTrigger: 3, 8 더 있음… }

The permission is validated, and mod_security was not loaded in apache module.

What is wrong in my trial?
I need your guide and comment about this error.

Yours. I appreciate in advanced.