There does not appear to be any such thread, and I can see deleted threads. If you used a corrupted file, that might account for it. Generally, posts are only deleted for a good reason, and if it was a single instance of an essay, then it would not have gone. If multiple copies were posted, it could have been a mistake when trying to delete the copies.
Threads are rarely deleted off the server, which is this only was I would not be able to see the deleted threads.
Can you shed any light on this?