New Error Again after finisihed add_item

A PHP Error was encountered
Severity: Notice
Message: Undefined variable: nav
Filename: admin/dashboard.php
Line Number: 28
Backtrace:
File: C:\xampp\htdocs\projek\application\views\admin\dashboard.php
Line: 28
Function: _error_handler
File: C:\xampp\htdocs\projek\application\libraries\Template.php
Line: 14
Function: view
File: C:\xampp\htdocs\projek\application\controllers\Admin.php
Line: 13
Function: admin
File: C:\xampp\htdocs\projek\index.php
Line: 315
Function: require_once
-----------------------------------------
A PHP Error was encountered
Severity: Notice
Message: Undefined variable: content
Filename: admin/dashboard.php
Line Number: 32
Backtrace:
File: C:\xampp\htdocs\projek\application\views\admin\dashboard.php
Line: 32
Function: _error_handler
File: C:\xampp\htdocs\projek\application\libraries\Template.php
Line: 14
Function: view
File: C:\xampp\htdocs\projek\application\controllers\Admin.php
Line: 13
Function: admin
File: C:\xampp\htdocs\projek\index.php
Line: 315
Function: require_once