Warning: Trying to access array offset on value of type bool in /customers/b/d/3/goethe-verlag.com/httpd.www/database/common.class.php on line 499

Fatal error: Uncaught TypeError: Cannot access offset of type string on string in /customers/b/d/3/goethe-verlag.com/httpd.www/book2/01.php:6
Stack trace:
#0 /customers/b/d/3/goethe-verlag.com/httpd.www/book2/index.php(108): include_once()
#1 {main}
  thrown in /customers/b/d/3/goethe-verlag.com/httpd.www/book2/01.php on line 6