The Table at the top of your code has align="left". Anything you add after that code will move to the right not bottom as intended. So replace:
Code:
<table id="post$post[postid]" class="tborder" cellpadding="7" cellspacing="0" border="0" width="100%" align="left">
With:
Code:
<table id="post$post[postid]" class="tborder" cellpadding="7" cellspacing="0" border="0" width="100%" align="center">
Re-add my code as provided in the other post and you'll separate the posts from one another.