编译错误：未找到：使用Scala时在Play框架中对nonEmptyText赋值

package controllers

import play.api._
import play.api.data.Form
import play.api.mvc._



import _root_.scala.xml.Text


object Application extends Controller {

  def index = Action {
    Redirect(routes.Application.tasks)
  }


  def deleteTask(id: Long) = TODO

  val taskForm = Form(
  "label" -> nonEmptyText
)
def tasks = Action {
  Ok(views.html.index(Task.all(),taskForm))
}

  def newTask = Action { implicit request =>
  taskForm.bindFromRequest.fold(
    errors => BadRequest(views.html.index(Task.all(),errors)),label => {
      Task.create(label)
      Redirect(routes.Application.tasks)
    }
  )
}
}

我正在使用Play 2.0框架.我错在哪里得到这样的错误？