Download the newer ZIP file that the original post has been updated with. I've dropped the date to another line to prevent the overlapping

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If you've already made quite a few modifications to your install, then simply replace your forumhome_lastpostby template with the following:
HTML Code:
<div style="width: 200px;" align="$stylevar[left]">
<div style="clear:both">
<a href="showthread.php?$session[sessionurl]goto=newpost&t=$lastpostinfo[lastthreadid]" title="<phrase 1="$lastpostinfo[lastthread]">$vbphrase[go_first_unread_in_thread_x]</phrase>"><strong>$lastpostinfo[trimthread]</strong></a>
</div>
<div style="float: left;">
<phrase 1="member.php?$session[sessionurl]find=lastposter&f=$lastpostinfo[forumid]" 2="$lastpostinfo[lastposter]">$vbphrase[by_x]</phrase>
<div style="float: right;">
<a href="showthread.php?$session[sessionurl]goto=lastpost&t=$lastpostinfo[lastthreadid]"><img class="inlineimg" src="$stylevar[imgdir_button]/lastpost.gif" alt="$vbphrase[go_to_last_post]" border="0" /></a> $lastpostinfo[lastpostdate] <if condition="!$show['detailedtime']"><span class="time">$lastpostinfo[lastposttime]</span></if>
</div>
</div>
</div>