Fatal error: Uncaught Error: Using $this when not in object context

I found the the solution and everything works now

I just removed: &$this,

giving :

self::pixgridder_admin( array( 'register_options' ) );

Hata!: SQLSTATE[HY000] [1045] Access denied for user 'divattrend_liink'@'localhost' (using password: YES)