package testproject;
import org.openqa.selenium.By;
import org.openqa.selenium.WebDriver;
import org.openqa.selenium.WebElement;
import org.openqa.selenium.firefox.*;
Are you certain your page is completely loaded after you sign in?
Did you set a timeout for your webdriver? (how long it has to wait for elements). Probably it reads your html before it's completey loaded.
Webdriver driver = new FirefoxDriver();
driver.manage().timeouts().implicitlyWait(50, TimeUnit.SECONDS);
To find out quickly if this is the problem do Thread.sleep(8000)
after you do wb2.click();