Permission declined to write to file

On xamppp I have в php рукописный шрифт that writes some восходит that is posted to it, over в text file. But when I try an run it I get

php рукописный шрифт:

<?php
$file = 'xy.txt';
// Opens the file to load the current content
$current = file_get_contents($file);
// Adds the data
$current .= "Hello\n";
// Writes the content back to the file
file_put_contents($file, $current);
?>