This happens on a few posts and is being noted as soon as we find older posts that still report this error. It was due to a database crash a few months back.
No posts are actually missing, it's due to a problem in the post count database not equalling up to the actual number of posts. For example, a post might have 6 replies, but the database thinks it has 12. If it switches to a second page at 10 posts, it will try to redirect you to a second page of posts that doesn't exist. All the posts are, in fact, still intact, just on page one.
The post you posted is not lost -- It was just added to a previous page in that same thread. Ignore the "missing page error", go back to the main thread, and go to a previous page, rather than the "missing last page"
"No posts exist in this topic"
