Missing flood protocol configuration

import scala.concurrent.duration._
​
import io.gatling.core.Predef._
import io.gatling.http.Predef._
import io.gatling.jdbc.Predef._
​
// Mandatory, you must import Flood libraries
import flood._
​
class TestPlan extends Simulation {
​
  // Optional, Flood will pass in threads, rampup and duration properties from UI
  val threads   = Integer.getInteger("threads",  10)
  val rampup    = Integer.getInteger("rampup",   10).toLong
  val duration  = Integer.getInteger("duration", 15).toLong
​
  // Mandatory, you must use httpConfigFlood
  val httpProtocol = httpConfigFlood
    .baseURL("http://google.com/")
    .acceptHeader("text/html,application/xhtml+xml,application/xml;")
    .acceptEncodingHeader("gzip, deflate")
​
  val scn = scenario("Scenario Name")
    .exec(http("first_page")
    .get("/"))
    .pause(1000 milliseconds, 5000 milliseconds)
​
  setUp(scn.inject(ramp(10 users) over (60 seconds))).protocols(httpProtocol)
}