我不知道我做错了什么。我没有编写此代码，但我在WordPress中收到以下错误：

wpdb：：prepare（）的查询参数必须有占位符。此消息是在版本3.9中添加的。

<?php

        echo \'<div class="client_list"><input type="checkbox" name="check_all" value="0" class="" id="check_all" /> Check All</div>\';


        $send_message_lists = get_post_meta($post->ID, wpvbxcon::smslist_smsclient, true);
        if(!is_array($send_message_lists))
            $send_message_lists = array();
        //print_r($send_message_lists);
        foreach($lists as $list)
            {   

                $q = "SELECT COUNT(*) FROM $wpdb->postmeta m JOIN $wpdb->posts p ON p.ID = m.post_id WHERE meta_key = \'_wpvbx_subscription\' AND meta_value = $list->ID AND post_status = \'publish\';";
                $subscriber_count = $wpdb->get_var($wpdb->prepare($q));

                $checked = \'\';
                if(in_array($list->ID, $send_message_lists))
                    $checked = \'checked="checked"\';

                if( current_user_can( \'_wpvbx_access_list_\'.$list->ID ) || current_user_can(\'administrator\') )
                    printf(\'<div class="client_list"><input type="checkbox" name="lists[]" value="%d" class="list" %s /> %s (%d)</div>\', $list->ID, $checked, $list->post_title, $subscriber_count);
            }
        echo \'<div style="clear:both;"> </div>\';


        ?>