Looking at this more this may be a left over glitch from your previous problem. so maybe just re-indexing may solve the issue.
The post "NO" has a weird file name. It almost looks like a date then the actual file number.200904301655.html
So I would look for that file or 1655.html
I do recall that each forum had a separate folder and it had something called forumthreads.cgi which held the index of posts. Then there is a separate file for each post.
