如何忽略Kohana中的通知或检查是否反对？ 我做错了什么？

Question

$dom=new DOMDocument();
@$dom->loadHTML($cl);
$xpath=new DOMXpath($dom);

$dish_l=$xpath->query("/html/body/div/table[5]/tr/td/div/div");
echo $dish_l->length;

for($index=0;$index<$dish_l->length;$index++)
{
    if( ($dish_id->item(0)->nodeValue) ) //I no need empty <div> blocks and this idea works perfect
    {   

    }
}

but I got "Notice: Trying to get property of non-object" if it just this php script I just disable show php errors and everything fine. and I try to use it with Kohana and "Notice" appear again, script stop with ErrorException. I tried some tips

for($index=0;$index<$dish_l->length;$index++)
{
   if(!is_object ($dish_id ) )//but it is not works
     {
     }
     else
     {
        if( ($dish_id->item(0)->nodeValue) ) 
        {   
        }    
     }
}

How to ignore notice in Kohana or check is it object?