Mtb specialized fsr xl

TypeError Object
(
    [message:protected] => Cannot access offset of type string on string
    [string:Error:private] => 
    [code:protected] => 0
    [file:protected] => /var/www/vhosts/casinuevo.net/httpdocs/app_verano/header.php
    [line:protected] => 191
    [trace:Error:private] => Array
        (
            [0] => Array
                (
                    [file] => /var/www/vhosts/casinuevo.net/httpdocs/app_verano/ficha_escritorio.php
                    [line] => 2436
                    [function] => include_once
                )

            [1] => Array
                (
                    [file] => /var/www/vhosts/casinuevo.net/httpdocs/ficha.php
                    [line] => 36
                    [args] => Array
                        (
                            [0] => /var/www/vhosts/casinuevo.net/httpdocs/app_verano/ficha_escritorio.php
                        )

                    [function] => include
                )

        )

    [previous:Error:private] => 
)