The reason why the "last post" link doesn't appear to be working correctly is because all of the original threads in GameBanshee News are not considered posts by vBulletin. All of the news is submitted through an external script for the main website, which in turn inserts the same news into MySQL for vBulletin to "see." The news isn't actually posted through conventional means in vBulletin, so each original news item isn't logged as a post. Therefore, the only "last posts" in that forum are going to be user comments.
Hopefully that makes sense
. The only way to fix it would be to totally overhaul the way news is submitted and I don't see that happening anytime soon.