php file manager error on array

Question

Good afternoon, im doing a php file manager and when i was trying to see te output, and all works in conditions i see those erros in my browser:

Warning: Undefined array key "file" in C:\xampp\htdocs\TESTE\index.php on line 33
Warning: Undefined array key "file" in C:\xampp\htdocs\TESTE\index.php on line 39
Warning: Undefined array key "file" in C:\xampp\htdocs\TESTE\index.php on line 50
Warning: Undefined array key "do" in C:\xampp\htdocs\TESTE\index.php on line 51
Warning: Undefined array key "do" in C:\xampp\htdocs\TESTE\index.php on line 77
Warning: Undefined array key "do" in C:\xampp\htdocs\TESTE\index.php on line 82
Warning: Undefined array key "do" in C:\xampp\htdocs\TESTE\index.php on line 90
Warning: Undefined array key "do" in C:\xampp\htdocs\TESTE\index.php on line 97

and those are some of my lines