MyBB Community Forums

^ can you make this clear - do you have class_plugins.php file in plugins folder ?
if so rename it as class_plugins.php.old & then check if the error gets fixed

no it is located in the inc folder

^ if referred problems still exist & if direct help required then
you may PM me temporary access to your forum admin panel & webhost control panel
[you can change your credentials later]

referred issue is fixed by removing a misplaced file "index.php" in the plugins folder