Sentry Knight thread exists but doesn't exist

I was searching for a thread for Sentry Knight in the Kongregate forum, but did not find any results.  So I tried to create a thread for it, but got a message that there was already a thread.  It provided a link (https://konghack.com/view_topic.php?t=8589), but following that link says the thread does not exist.

Is there a way to clear the thread that doesn't exist so a new thread can be posted?

Yeah, I'll get this fixed when I get home.