[cellarius]

The code in step No. 3 did not validate against xhtml for me. Instead I used the following:

<!-- Modified Thread Search Layout -->

<form action="forumdisplay.php" method="get">
<input type="hidden" name="s" value="$session[sessionhash]" />
<input type="hidden" name="f" value="$forumid" />
<input type="hidden" name="page" value="$pagenumber" />
<input type="hidden" name="pp" value="$perpage" />

<table class="tborder" cellpadding="$stylevar[cellpadding]" cellspacing="$stylevar[cellspacing]" border="0" width="100%" align="center">
<tr>
    <td class="thead"><phrase 1="$limitlower" 2="$limitupper" 3="$totalthreads">$vbphrase[showing_threads_x_to_y_of_z]</phrase></td>
</tr>
 <tr valign="top">
    <td class="alt1">
        <table cellpadding="3" cellspacing="0" border="0" align="center">
        <tr>
            <if condition="$prefix_options">
            <td><select name="prefixid" id="sel_prefixid">
                    <option value=""$prefix_selected[any]>$vbphrase[any_prefix_meta]</option>
                    <option value="-1"$prefix_selected[none]>$vbphrase[no_prefix_meta]</option>
                    $prefix_options
                </select></td>
            </if>
            <td><select name="sort" id="sel_sort">
                    <option value="title" $sort[title]>$vbphrase[thread_title]</option>
                    <option value="lastpost" $sort[lastpost]>$vbphrase[last_post_time]</option>
                    <option value="dateline" $sort[dateline]>$vbphrase[thread_start_time]</option>
                    <option value="replycount" $sort[replycount]>$vbphrase[number_of_replies]</option>
                    <option value="views" $sort[views]>$vbphrase[number_of_views]</option>
                    <option value="postusername" $sort[postusername]>$vbphrase[thread_starter]</option>
                    <if condition="$show['threadratings']"><option value="voteavg" $sort[voteavg]>$vbphrase[thread_rating]</option></if>
                </select></td>
            <td><select name="order" id="sel_order">
                    <option value="asc" $order[asc]>$vbphrase[ascending]</option>
                    <option value="desc" $order[desc]>$vbphrase[descending]</option>
                </select></td>
            <td><select name="daysprune" id="sel_daysprune">
                    <option value="1" $daysprunesel[1]>$vbphrase[last_day]</option>
                    <option value="2" $daysprunesel[2]>$vbphrase[last_2_days]</option>
                    <option value="7" $daysprunesel[7]>$vbphrase[last_week]</option>
                    <option value="10" $daysprunesel[10]>$vbphrase[last_10_days]</option>
                    <option value="14" $daysprunesel[14]>$vbphrase[last_2_weeks]</option>
                    <option value="30" $daysprunesel[30]>$vbphrase[last_month]</option>
                    <option value="45" $daysprunesel[45]>$vbphrase[last_45_days]</option>
                    <option value="60" $daysprunesel[60]>$vbphrase[last_2_months]</option>
                    <option value="75" $daysprunesel[75]>$vbphrase[last_75_days]</option>
                    <option value="100" $daysprunesel[100]>$vbphrase[last_100_days]</option>
                    <option value="365" $daysprunesel[365]>$vbphrase[last_year]</option>
                    <option value="-1" $daysprunesel[all]>$vbphrase[beginning]</option>
                </select></td>
            <td class="smallfont" align="$stylevar[right]" style="padding-top:$stylevar[cellpadding]px">
                <input type="submit" class="button" value="$vbphrase[show_threads]" />
            </td>
</tr>
        </table>    
    </td>
  </tr>
</table>
</form>

<form action="inlinemod.php?forumid=$forumid" method="post" id="inlinemodform">
<input type="hidden" name="url" value="$url" />
<input type="hidden" name="s" value="$session[sessionhash]" />
<input type="hidden" name="securitytoken" value="$bbuserinfo[securitytoken]" />
<input type="hidden" name="forumid" value="$forumid" />
<table class="tborder" cellpadding="$stylevar[cellpadding]" cellspacing="$stylevar[cellspacing]" border="0" width="100%" align="center" id="threadslist">
<tbody>
$announcebits
<!-- / Modified Thread Search Layout -->