url() problem: Unsupported operand types

Question

Hello, I have a problem with print url on view:

<?php foreach ($rows as $id => $row): ?>
    <?php print $row; ?>
<?php 
?>
<a href="<?php echo url('vote', 'id='.$row->nid) ?>" class="voter"></a>
<?php endforeach; ?>

I am getting Fatal error: Unsupported operand types in /{uri}/includes/common.inc on line 1436

Could somebody help me resolve this error?

Regards