in the template forumhome_lastpostby,
find
Code:
<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>$lastpostinfo[trimthread]</strong></a>
replace with
Code:
<a href="showthread.php?$session[sessionurl]t=$lastpostinfo[lastthreadid]"><strong>$lastpostinfo[trimthread]</strong></a>