Method Timeout exception

private void BtnBuildClick(object sender, EventArgs e)
        {
            _itemsToLoad.CompleteAdding();
            Task[] runnerTasks = new Task[1];
            runnerTasks[0] = Task.Factory.StartNew(RunBuilder, TaskCreationOptions.LongRunning);
            Task.Factory.ContinueWhenAll(runnerTasks, completedTasks => TaskIsComplete());

            foreach (item in _itemsToLoad.GetConsumingEnumerable())
                WaitUntil3rdPartyIsReady();
        }


 public void WaitUntil3rdPartyIsReady()
        {
            //if this takes longer than X seconds, I want to let the user know via a message box
            //and then exit the thread and do some cleanup (close 3rd party programs that were opened as child windows)

            while (!_Window.ChildWindows.Exists(c => c.Class == "TEdit"))
            {

            }
            while (!_Window.ChildWindows.Find(c => c.Class == "TEdit").IsVisible)
            {

            }
        }