problem with code

Hello,
I tried to use the code that Send Arduino data to the Web , From :

but when I want to upload code on Arduino It shows me the following error:

C:\Users\zaher_Ba_AJ\Desktop\FSA6ST4HXB3V05E\FSA6ST4HXB3V05E.ino: In function 'void loop()':

FSA6ST4HXB3V05E:45: error: invalid operands of types 'const char*' and 'const char [7]' to binary 'operator+'

  data = "temp1=" + t + "&hum1=" + h;

                        ^

Multiple libraries were found for "DHT.h"
 Used: C:\Users\zaher_Ba_AJ\Documents\Arduino\libraries\DHT_sensor_library
 Not used: C:\Users\zaher_Ba_AJ\Documents\Arduino\libraries\F6HK8XBHXB3V7JK
exit status 1
invalid operands of types 'const char*' and 'const char [7]' to binary 'operator+'

I hope to found solution for this problem.

Please post your code, in code tags

Have you read the page that you linked to ? Others had the same problem and solutions were offered.

#include <DHT.h>
#include <Ethernet.h>
#include <SPI.h>

byte mac[] = { 0x00, 0xAA, 0xBB, 0xCC, 0xDE, 0x01 }; // RESERVED MAC ADDRESS
EthernetClient client;

#define DHTPIN 2 // SENSOR PIN
#define DHTTYPE DHT11 // SENSOR TYPE - THE ADAFRUIT LIBRARY OFFERS SUPPORT FOR MORE MODELS
DHT dht(DHTPIN, DHTTYPE);

long previousMillis = 0;
unsigned long currentMillis = 0;
long interval = 250000; // READING INTERVAL

int t = 0;	// TEMPERATURE VAR
int h = 0;	// HUMIDITY VAR
String data;

void setup() { 
	Serial.begin(115200);

	if (Ethernet.begin(mac) == 0) {
		Serial.println("Failed to configure Ethernet using DHCP"); 
	}

	dht.begin(); 
	delay(10000); // GIVE THE SENSOR SOME TIME TO START

	h = (int) dht.readHumidity(); 
	t = (int) dht.readTemperature(); 

	data = "";
}

void loop(){

	currentMillis = millis();
	if(currentMillis - previousMillis > interval) { // READ ONLY ONCE PER INTERVAL
		previousMillis = currentMillis;
		h = (int) dht.readHumidity();
		t = (int) dht.readTemperature();
	}

	data = "temp1=" + t + "&hum1=" + h;

	if (client.connect("www.*****.*************.com",80)) { // REPLACE WITH YOUR SERVER ADDRESS
		client.println("POST /add.php HTTP/1.1"); 
		client.println("Host: *****.*************.com"); // SERVER ADDRESS HERE TOO
		client.println("Content-Type: application/x-www-form-urlencoded"); 
		client.print("Content-Length: "); 
		client.println(data.length()); 
		client.println(); 
		client.print(data); 
	} 

	if (client.connected()) { 
		client.stop();	// DISCONNECT FROM THE SERVER
	}

	delay(300000); // WAIT FIVE MINUTES BEFORE SENDING AGAIN
}

data = "temp1=" + t + "&hum1=" + h;See reply #2