Working plugin code breaks admin

Not sure if this is the actual answer for this but on line 252 of the pastebin link change:

 <form action="'.site_url().'/wp-admin/admin.php/options-general.php" method="get">

to

 <form action="'.admin_url('options-general.php').'" method="get">

When I submitted the form in the settings it giving me a not found error.

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