Warning in sql output

For some reason I get this:
Notice: Undefined index: entry_id in /htdocs/admincp/plugins/pi.poll.php on line 34

And here’s my code:


class Poll
{

var $return_data  ;
	

	
  
  function Poll()
  {
    global $DB,$TMPL;
	$poll_title = 'Is this person naughty or not?';
	$entry_id = $TMPL->fetch_param('entry_num');
	$results = $DB->query("SELECT * FROM poller WHERE entry_id = '$entry_id'");
	
	
	if(isset($results) !== '')
	{
		
		
		if( $results->row['entry_id'] !== $entry_id)
		{
			$data = array(
			'ID' => '', 
			'pollerTitle' => $poll_title, 
			'entry_id' => $entry_id, 
			
			);
			$sql = $DB->insert_string('poller',$data);	
			$DB->query($sql);
			echo $last_entry = $DB->insert_id;	
		}
		else
		{
			echo 'This entry is already in the system so run this code';
	
		}
	}
	else
	{
		echo '2nd section of the script';

  	}
 
  }
  
  }

The script works because the data is inserted into the db but it annoys me that I’m getting a notice of some sort. It might screw something up in the long run so…