This is the line you want to get rid of?
HTML Code:
<td class="alt2" nowrap="nowrap">$forum[lastpostinfo]</td>
How about
:
HTML Code:
<td class="alt2" nowrap="nowrap"><if condition="$forum['forumid'] == '158'"> <else />$forum[lastpostinfo]</if></td>
That should put a space/blank in if it is forumid 158, but it will show the lastpostinfo for all other forums. (I have not tried it.)