[Ask] _FFXpath and _FFObj Failed to find object

_FFStart("http://www.amazon.com/dp/B0091KD43U", Default)
$oDesc = _FFXpath(".//div[@class='productDescriptionWrapper']")

$desc = _FFObj($oDesc,"textContent")
ConsoleWrite($desc)

FFau3.xpath=null;try{FFau3.xpath=FFau3.WCD.evaluate(".//div[@class='productDescriptionWrapper']",FFau3.WCD,null,XPathResult.FIRST_ORDERED_NODE_TYPE,null).singleNodeValue;}catch(e){'_FFXPath_Error: '+e;};
__FFRecv:
__FFSend: try{FFau3.xpath.hasAttribute('textContent')}catch(e){'_FFCmd_Err';};
__FFRecv: _FFCmd_Err
__FFSend: try{FFau3.xpath.textContent}catch(e){'_FFCmd_Err';};
__FFRecv: _FFCmd_Err
_FFObj ==> No match: $sObject not found: FFau3.xpath.textContent