.i want to go to a frame in which some links are there....Once I come in to a fram.i want to click all the links one by one..using webdriver...below is the code i have written.plz suggest me

public static void main(String[] args) {
        // TODO Auto-generated method stub
        WebDriver driver=new FirefoxDriver();
        driver.get("http://timesofindia.indiatimes.com/home");
    WebDriverWait wait= new WebDriverWait(driver,200);
        wait.until(ExpectedConditions.presenceOfElementLocated(By.id("riShop")));
        driver.switchTo().frame("riShop");

        List<WebElement> lst=driver.findElements(By.tagName("a"));
        for(inti=0;i<lst.size();i++){
            lst.get(i).click();
            driver.navigate().back();


        }
            }
    }       

    }

In the above code....only the first link gets clicked and then i get exception like..unable to locate the next element.....NoSuchException plz suggest me something about it...