[nhawk]

Sometimes it's the obvious that will kill you.

Newthread editor is a form and you can't have a form inside of a form like you have now.

Just add the <div> sections without the form attributes.

<vb:if condition="$show['member'] AND $vboptions['enable']">
	<div>Select ThreadID To Post: 
		<select id="threadid" name="threadid" onChange="javascript:get(this.parentNode);">
<option value="0" selected="selected">0</option>
			{vb:raw mytest}
		</select>
	</div>
	<div id="threadid"></div>
</vb:if>