error gatling session

well, Am new working with gatling am in training, I hava a error, I attached the error scrennshot, some one can I help me with these, this is the code, I am a index with the login form that will go to sesion1.jsp using a post method.

if some one can heplme I am greatful, this is the code

package basic

import io.gatling.core.Predef._
import io.gatling.http.Predef._
import io.gatling.jdbc.Predef._
import io.gatling.http.Headers.Names._
import scala.concurrent.duration._
import bootstrap._
import assertions._

class BasicExampleSimulation extends Simulation {

val httpProtocol = http
.acceptEncodingHeader(“gzip, deflate”)

val headers_1 = Map(
“Keep-Alive” → “115”)

val headers_3 = Map(
“Keep-Alive” → “115”,
“Content-Type” → “application/x-www-form-urlencoded”)

val headers_6 = Map(
“Accept” → “application/json, text/javascript, /; q=0.01”,
“Keep-Alive” → “115”,
“X-Requested-With” → “XMLHttpRequest”)

val scn = scenario(“prueba geiner”)
.group(“Login”) {
.pause(12, 13)

setUp(scn.inject(ramp(5 users) over (1 seconds)))
.assertions(, details(“Login” / “request_3”).responseTime.max.lessThan(3000),

I think that’s a bug that’s already been fixed.
Annoying but not harmful.

If you want to get rid of it, you’ll have to upgrade to current snapshot:

Thanks so much!