hi kenchan.
At first, thank you for buying my book.
The codes looks safe enough.
But I think there are no necessity to hack header.php.
<!-- Display left blocks if any -->
<{if count($xoops_lblocks) > 0}>
<td id="leftcolumn">
<!-- Start left blocks loop -->
<{foreach item=block from=$xoops_lblocks}>
<{if $block.title}>
<div align=center class="blockTitle">
<{$block.title}>
</div>
<{/if}>
<div class="blockContent"><{$block.content}></div>
<{/foreach}>
<!-- End left blocks loop -->
</td>
<{/if}>
I'm sorry that I don't check the code woks or not