Formdata在处理后丢失

I have a form which was working fine earlier. After a server upgrade to PHP 5.3 I now have a problem.

When my loop in the form (number of products) exceeds 9 or 10 lines, the form data is then lost, when sending it to the server.

What can be the problem? I am unable to understand why smaller loops are processed nicely and longer ones are not.

Below I have added some small parts of the code to show how the form is built.

<table id="top_header" class="pop_up" cellspacing="10" cellpadding="5" width="100%">
    <tr class="floating header">
        <td class="regel"><?php echo $lang['regel']; ?></td>

    </tr>
    <tr>
        <td class="regel">
            <input type="text" name="regel[]" value="<?php echo $regel; ?>" size="1" style="background-color: #e7e7e9" readonly="readonly" />
        </td>
    </tr>
    <tr>
        <td><input type="submit" class="btn_ok" onclick="this.disabled=true,this.form.submit();" value="<?php echo $lang['form_submit']; ?>" /> <input type="reset" class="btn_rst" value="<?php echo $lang['form_cancel']; ?>" /></td>
    </tr>
</table>

<?php
$regel= trim(mysql_real_escape_string($_POST['regel']));
?>

I have also added the complete file to http://www.thure.nl/php_test/calculatie_plaat_edit.rar