How to fix
Locate the line in the admin/applications/core/modules_public/global/login.php file:
if ( count($additionalForm[1]) )
Replace it with:
if ($additionalForm[1] && count($additionalForm[1]))
Locate the line in the admin/applications/core/modules_public/global/login.php file:
if ( count($additionalForm[1]) )
Replace it with:
if ($additionalForm[1] && count($additionalForm[1]))