表单未将信息插入mysql表

嗨，我的论坛评论表单有问题。基本上，我试图允许用户阅读用户的帖子并对其进行评论，表单数据假设插入到mysql中。

我需要插入的值是comment_id，它是用户的会话id，post_id是他们评论的帖子的id以及他们键入的内容。

出于某种原因，这并没有被插入到mysql中，而是在没有任何错误的情况下返回了我的成功消息。有人能告诉我哪里出了问题吗。

感谢

<?php
        $page_title = "Read Post";
        include('includes/header.php'); 
        include ('includes/mod_login/login_form2.php');  ?>
        <?php
        confirm_logged_in();

        if (isset ($_GET['post'])) {
        $forum_id = $_GET['post'];
    }
    ?>
    <?php include('includes/copyrightbar.php'); ?>
    <?
    $read_forum_set = read_forum_set();
            while ($forum = mysql_fetch_array($read_forum_set)) {?>
    <div class="modtitle">
    <div class="modtitle-text"><?php echo "{$forum['display_name']}"; ?>'s Forum Post</div>
    <? } ?>
    </div>
    <div class="modcontent57">

    <br /><br /><br/><br/>
    <div class="forum">
    <div class="forum-pic"><?php echo "<img src='"data/photos/{$_SESSION['user_id']}/_default.jpg'" width='"100'" height='"100'" border='"0'" align='"right'" class='"img-with-border-forum'" />";?>
    </div>
    <div class="message-links">
    <strong><a href="forum.php"><< Back to Forum</a>
    </div> 
    <br /><br /><br/><br/>
    <?php 
        $datesent1 = $forum['date_sent'];  ?>
    <?php
            $read_forum_set = read_forum_set();
            while ($forum = mysql_fetch_array($read_forum_set)) {
            $prof_photo = "data/photos/{$forum['user_id']}/_default.jpg";
            $result = mysql_query("UPDATE ptb_forum SET ptb_forum.read_forum='1' WHERE ptb_forum.id='$forum'") 
    or die(mysql_error()); 
    ?>
    <div class="message-date">
    <?php echo "".date('D M jS, Y  -  g:ia', strtotime($forum['date_sent'])).""; ?></div>

    <div class="img-with-border-frm-read"><?php echo "<a href='"profile.php?id={$forum['from_user_id']}'"><img width='"60px'" height='"60px'" src='"{$prof_photo}'"></a><br />"; ?></div>

    <?php echo "<div class='"forum-content2'"><div class='"forum_subject'"><strong>Subject:</strong></div><div class='"forum_subject2'"><i>{$forum['title']}</i></div><div class='"forum_body'"><strong>Post:<br/></strong></br ><i>{$forum['content']}</i></div></div>";?>

     <?php 
    // check if the review form has been sent
    if(isset($_POST['forum_comment']))
    {
        $content = $_POST['forum_comment'];
            //We remove slashes depending on the configuration
            if(get_magic_quotes_gpc())
            {
                    $content = stripslashes($content);
            }
            //We check if all the fields are filled
            if($_POST['forum_comment']!='')
            {

                {
                $sql = "INSERT INTO ptb_forum_comments (comment_id, post_id, content) VALUES (NULL, '".$_SESSION['user_id']."', '".$profile_id."', '".$content."');";
                mysql_query($sql, $connection);
                echo "<div class='"infobox-profile4'"><strong>Thank You</strong> - Your review has been sent for approval.</div>";
            } }
    }
    ?> 

     <?php if(isset ($_SESSION['user_id'])) { ?>

    <div class="forum-comment-box">
    <form action="<?php $_SERVER['PHP_SELF'] ?>" method="post">
    <textarea name="forum_comment" id="forum_comment" style="resize:none; height:100px; width:543px;"></textarea><input type="submit" name="send_button" id="send_button" style="float:right; margin-right:30px; text-align:center;" value="Reply to {$message['display_name']}" /></form></div>
    <? } } ?>

          </div>
          </div>

    <?php include('includes/footer.php'); ?>
    </div>