There was a narrow window in August I believe where we did completely lose about 15 day's worth of posts - the old forum crashed and was un-salvageable, and I had a 15-day old backup I was forced to recover everything from. If your post was in that period of time then unfortunately it is gone :/
My apologies. The new software is much easier to back up, and I have been making regular backups of both the whole site and forum's database. I am also creating redundant copies of the backups in multiple locations so that the information won't be lost if there are issues. The database is not wholly proprietary either (as was the old one), and is significantly easier to re-populate a forum with. (I have seen the death of too many really great forums from the lack of such controls, so I am doing my best to prevent this from happening in the future)
-Rocketman