[akanevsky]

Ok, I found the fix, thanks to Rabbit_Warren for giving me access to his board.

Problem source: Old version of the adv_editform template... (I'm still getting used to the product system).
Solution: Either download a new version of the XML, or replace the contents of adv_editform with the following:

<if condition="$bbuserinfo['editlevel'] > EDITLEVEL_AUTHOR">
<table class="tborder" cellpadding="$stylevar[cellpadding]" cellspacing="$stylevar[cellspacing]" border="0" width="100%" align="center">
<tr>
	<td class="tcat">
		<a style="float:$stylevar[right]" href="#top" onclick="return toggle_collapse('editpost_advanced')"><img id="collapseimg_editpost_advanced" src="$stylevar[imgdir_button]/collapse_tcat$vbcollapse[collapseimg_editpost_advanced].gif" alt="" border="0" /></a>
		$vbphrase[advedit_boxtitle]
	</td>
</tr>
<tbody id="collapseobj_editpost_advanced" style="$vbcollapse[collapseobj_editpost_advanced]">
	<tr>
		<td class="panelsurround" align="center">
		
		<div class="panel">
			<div style="width:$stylevar[formwidth]" align="$stylevar[left]">
			
				<div class="fieldset">
					<div>$vbphrase[advedit_boxdescription]</div>
				</div>
				
				<fieldset class="fieldset">
					<legend>$vbphrase[advedit_fieldset_title]</legend>
					<div style="padding:$stylevar[formspacer]px">
					
						<div>
							<label for="sb_editlevel">
								<select name="editlevel" id="sb_editlevel">
									<option value="0" <if condition="$adv_data['editlevel'] == EDITLEVEL_AUTHOR">selected="selected"</if>>
										$vbphrase[advedit_editlevel_author]
									</option>
									<option value="1" <if condition="$adv_data['editlevel'] == EDITLEVEL_MOD">selected="selected"</if>>
										$vbphrase[advedit_editlevel_mod]
									</option>
									<if condition="$bbuserinfo['editlevel'] >= EDITLEVEL_SMOD">
									<option value="2" <if condition="$adv_data['editlevel'] == EDITLEVEL_SMOD">selected="selected"</if>>
										$vbphrase[advedit_editlevel_smod]
									</option>
									</if>
									<if condition="$bbuserinfo['editlevel'] == EDITLEVEL_ADMIN">
									<option value="3" <if condition="$adv_data['editlevel'] == EDITLEVEL_ADMIN">selected="selected"</if>>
										$vbphrase[advedit_editlevel_admin]
									</option>
									</if>
								</select>
								$vbphrase[advedit_editlevel_andabove]
							</label>
						</div>
						
						<if condition="$bbuserinfo['editlevel'] == EDITLEVEL_ADMIN">
						<div>
							<label for="tb_dateline">
								<input type="text" name="newday" value="$adv_data[mday]" size="1" maxlength="2" id="tb_dateline_day" />.
								<input type="text" name="newmonth" value="$adv_data[mon]" size="1" maxlength="2" id="tb_dateline_month" />.
								<input type="text" name="newyear" value="$adv_data[year]" size="3" maxlength="4" id="tb_dateline_year" />  -
								<input type="text" name="newhour" value="$adv_data[hours]" size="1" maxlength="2" id="tb_dateline_day" />:
								<input type="text" name="newminute" value="$adv_data[minutes]" size="1" maxlength="2"  id="tb_dateline_day" />
								$vbphrase[advedit_dateposted]
							</label>
						</div>
						<div>
							<label for="tb_username">
								<input type="text" name="newusername" value="$adv_data[username]" id="tb_username" /> $vbphrase[advedit_postauthor]
							</label>
						</div>
						<div>
							<label for="tb_ipaddress">
								<input type="text" name="newipaddress" value="$adv_data[ipaddress]" id="tb_ipaddress" /> $vbphrase[advedit_ipaddress]
							</label>
						</div>
						</if>
						
					</div>
				</fieldset>
				
			</div>
		</div>
		
		</td>
	</tr>
</tbody>
</table>
<br />
</if>