My problem is when i use xampp i see many error and when i use my web it has no error

Notice: Undefined index: action in C:\xampp\htdocs\xyz\index.php on line 3

Notice: Undefined index: usNick in C:\xampp\htdocs\xyz\config.php on line 11

Notice: Use of undefined constant setname - assumed 'setname' in C:\xampp\htdocs\xyz\config.php on line 31

Notice: Use of undefined constant setname - assumed 'setname' in C:\xampp\htdocs\xyz\config.php on line 31

Notice: Undefined index: usNick in C:\xampp\htdocs\xyz\config.php on line 34

Notice: A session had already been started - ignoring session_start() in C:\xampp\htdocs\xyz\data.php on line 2

Notice: Undefined index: r in C:\xampp\htdocs\xyz\data.php on line 4

Notice: Undefined index: ucNick in C:\xampp\htdocs\xyz\data.php on line 8

I have tried many time changing things in Setting, Security, Privileges etc but nothing changed, I want to know if im missing something out

Thanks