i'd suggest to do this change on SHOWTHREAD:
Code:
<div class="smallfont" align="center">
<strong>«</strong>
<a href="showthread.php?$session[sessionurl]t=$getnextoldest[threadid]">$vbphrase[prev_thread]</a>
<if condition="$getnextnewest[threadid] > 0">
|
<a href="showthread.php?$session[sessionurl]t=$getnextnewest[threadid]">$vbphrase[next_thread]</a>
<strong>»</strong>
</if>
</div>