The screenshot is here: http://farm3.static.flickr.com/2411/2274127483_df5296912f_o.jpg

In the left is view mode and the right is edit mode.
I check the contents of the TopicClass object in my topic page, both the properties title and post is empty, when I enter something in these 2 properties, everything is displayed properly.
I view the code in BBCode.TopicClassSheet, I don't see any code assign the value for this 2 properties, I don't know the Bulletin_Board.xar I downloaded is the same as yours.
 
#if ($context.action == 'inline' && $doc.isNew() == 'true')
$msg.bb_entertopictitle<br /> $doc.display('topictitle')
$msg.bb_entertopicpost<br /> $doc.display('topicpost')
#set($newtopictitle = $request.topictitle)
#if($newtopictitle)
#set($newtopictitle = $newtopictitle.replaceAll('"',"'"))
<script type="text/javascript">
var topictitle = "${newtopictitle}";
{pre}
document.forms.inline["BBCode.TopicClass_0_topictitle"].value = topictitle;
{/pre}
</script>
#end
#elseif..
#end