NoSuchElementFound after upgrading to dojo 1.9.1

Question

I'm working in a web app where webdriver tests were running succesfully in Firefox 29. The web app was upgraded from dojo 1.7.2 to 1.9.1 and now Selenium 2.44.0 throws a NoSuchElementException. The exception comes from this function:

pTestCase._waitForElementByXPath("/html/body/div[@style='opacity: 0; display: none;']");

public WebElement _waitForElementByXPath(String elementXPath) throws InterruptedException {
    return _waitForElementByXPath(elementXPath,STANDARD_TIMEOUT);
}

public WebElement _waitForElementByXPath(String elementXPath, int timeout) throws InterruptedException {
    driver.manage().timeouts().implicitlyWait(timeout, TimeUnit.SECONDS);
    return driver.findElement(By.xpath(elementXPath));      
}

Does anyone knows how I got the web element through the xpath before, and now I can't with the new version of dojo?

Selenium version: 2.44.0 Firefox version: 29.0 Dojo version: 1.9.1