Sugar CRM Soap call not working properly

Question

I am using a soap call to sugarcRM instance which is given below

$response = $client->call('get_entry_list',array('session'=>$session_id,'module_name'=>'itf_Apartments', "query"=>"itf_apartments_cstm.neighborhood_c='$neighborhood'", 'order_by'=>'','offset'=>'','select_fields'=>array($type)));

// Check for a fault
if ($client->fault) {
              echo 'Fault<pre>';
                 print_r($result);
                 echo '</pre>';
} else {
// Check for errors
$err = $client->getError();
if ($err) {
 // Display the error
 echo 'Error<pre>' . $err . '</pre>';
} else {
 // Display the result
 echo 'Result<pre>';
 echo "</br></br></br> Result Response </br>";
 var_dump($response);

 echo '</pre>';
}

}

Sometimes i am getting the correct result.. sometimes it returns the error "XML error parsing SOAP payload on line 1: Invalid document end"

Can anyone help me on this ???