WARNING(2): "mysqli_set_charset(): Error executing query"

WARNING(2): "session_start(): Cannot send session cookie - headers already sent by (output started at /home/www/public_html/shop/gm/classes/ErrorHandler.php:419)"

WARNING(2): "session_start(): Cannot send session cache limiter - headers already sent (output started at /home/www/public_html/shop/gm/classes/ErrorHandler.php:419)"

WARNING(2): "Cannot modify header information - headers already sent by (output started at /home/www/public_html/shop/gm/classes/ErrorHandler.php:419)"

WARNING(2): "Cannot modify header information - headers already sent by (output started at /home/www/public_html/shop/gm/classes/ErrorHandler.php:419)"