.
Use table instead of divs ... if you wanna make sure they are in one line.
PS. If user name is too long it will stretch the last post column.
Tried and tested code below:
HTML Code:
<if condition="$show['lastpostinfo']">
<div class="smallfont" align="$stylevar[left]">
<div>
<span style="white-space:nowrap">
<if condition="$show['icon']"><img class="inlineimg" src="$icon[iconpath]" alt="$icon[title]" border="0" /></if>
<if condition="$lastpostinfo['prefix']">
$lastpostinfo[prefix]
</span><if condition="is_browser('safari')"><!--bug#24775--> </if>
<span style="white-space:nowrap">
</if>
<a href="showthread.php?$session[sessionurl]goto=newpost&t=$lastpostinfo[lastthreadid]" style="white-space:nowrap" title="<phrase 1="$lastpostinfo[lastthread]">$vbphrase[go_first_unread_in_thread_x]</phrase>"><strong>$lastpostinfo[trimthread]</strong></a></span>
</div>
<table align="center" width="100%" cellpadding="2" cellspacing="0" border="0">
<tr>
<td align="left" style="white-space:nowrap" class="smallfont">
<phrase 1="member.php?$session[sessionurl]find=lastposter&f=$lastpostinfo[forumid]" 2="$lastpostinfo[lastposter]">$vbphrase[by_x]</phrase>
</td>
<td align="right" style="white-space:nowrap" class="smallfont">
$lastpostinfo[lastpostdate] <if condition="!$show['detailedtime']"><span class="time">$lastpostinfo[lastposttime]</span></if>
<a href="showthread.php?$session[sessionurl]p=$lastpostinfo[lastpostid]#post$lastpostinfo[lastpostid]">
<img class="inlineimg" src="$stylevar[imgdir_button]/lastpost.gif" alt="$vbphrase[go_to_last_post]" border="0" /></a>
</td>
</tr>
</table>
</div>
<else />
<div class="smallfont" align="$stylevar[right]">
$lastpostinfo[lastpostdate] <if condition="!$show['detailedtime']"><span class="time">$lastpostinfo[lastposttime]</span></if>
<a href="showthread.php?$session[sessionurl]p=$lastpostinfo[lastpostid]"><img class="inlineimg" src="$stylevar[imgdir_button]/lastpost.gif" alt="$vbphrase[go_to_last_post]" border="0" /></a>
</div>
</if>
.