Try this,maybe it will fix your problem
in Display.template.php
// Can they reply? Have they turned on quick reply?
if ($context['can_reply'] && !empty($options['display_quick_reply']))
echo '
<a href="', $scripturl, '?action=post;quote=', $message['id'], ';topic=', $context['current_topic'], '.', $context['start'], ';num_replies=', $context['num_replies'], ';sesc=', $context['session_id'], '" onclick="doQuote(', $message['id'], ', \'', $context['session_id'], '\'); return false;">', $reply_button, '</a>';
if ($context['can_reply'])
echo '
<a href="', $scripturl, '?action=post;quote=', $message['id'], ';topic=', $context['current_topic'], '.', $context['start'], ';num_replies=', $context['num_replies'], ';sesc=', $context['session_id'], '">', $reply_button, '</a>';