Object invoked disconnect from client at website deployment

I fix my problem,

I was getting a problem cause the time i was getting the document object and the time i was doing a query selector. The page was refreshing (due to the first load) and then my object got disconnected when trying to do the querySelector.

Basicly i did :

try
{
   fromElement = getCurrentPage().contentDocument;
   elemFound = fromElement.querySelector(cssSelector);
}
catch (ex)
{
    fromElement = null;
    elemFound = null;
}

So if the problem occur i just continue my loop and return null if I don't get what i want ater the timeout (for my case, it's doing what i want).