How can relative paths in PHP code cause errors like "Failed opening required 'globals.inc.php'"?

Relative paths in PHP code can cause errors like "Failed opening required 'globals.inc.php'" when the script is unable to locate the file it is trying to include or require. To solve this issue, it is recommended to use absolute paths or adjust the relative paths to correctly reference the file location.

// Using absolute path to include 'globals.inc.php'
require_once(__DIR__ . '/globals.inc.php');