I am using Selenium IDE and Selenium web driver testng in eclipse .. my testing is against ZK application ..
the test case works fine on Selenium IDE ..
I'm not sure but try and see if following works for you. First, you've to make that element visible before interacting with it -
WebElement element = driver.findElement(By.xpath("//div[2]/div[2]"));
((JavascriptExecutor) driver).executeScript("arguments[0].scrollIntoView(true);", element);
The above code will scroll down till the element is visible and then you can click on it.