Warning "Unable to open the device" - XAMPP

Hi at all :slight_smile: I’ve a problem with serial communication from PHP to Arduino.
Errors:

Warning: Unable to open the device in C:\xampp\htdocs\progetto\librerie\php_serial.class.php on line 187
Warning: Device must be opened in C:\xampp\htdocs\progetto\librerie\php_serial.class.php on line 608

I’m using the library php_serial.class.php, my OS is Windows and the port of Arduino Uno is COM13.
PHP code:

<?php

error_reporting(E_ALL); 
ini_set("display_errors", 1);  

if (isset($_GET['action'])) {

    require("librerie/php_serial.class.php");

        $serial = new phpSerial();
        $serial->deviceSet("COM13");
        $serial->confBaudRate(9600);
        $serial->deviceOpen();
		sleep(2);

if ($_GET['action'] == "green1") {

        $serial->sendMessage("0");

} else if ($_GET['action'] == "green0") {

        $serial->sendMessage("1");
}

$serial->deviceClose();

}
?>

<!DOCTYPE html>
<html>
<head>
<title>ARDUINO</title>
</head>
<body>

<h1> ARDUINO AND PHP COMMUNICATION </h1>

<a href="?action=green1">ON</a>

<a href="?action=green0">OFF</a>


</body>
</html>

Arduino code:

int green = 8;
int incomingbyte;

void setup()
{
  Serial.begin(9600);
  pinMode(green,OUTPUT);
}

void loop()
{
  if(Serial.available() > 0)
  {
    incomingbyte = Serial.read();
  }
  if(incomingbyte == '0'){
  digitalWrite(green,HIGH);
  }
  if(incomingbyte == '1'){
  digitalWrite(green,LOW);
  }
}