You can see any post you have made here:
http://forum.dead-donkey.com/search.php ... nt_sunrise
There are no bugs or computer glitches, if you get the message that something was submitted, it has been submitted. If you posted in violation in the rules, you get your topic locked, and then later deleted or moved to the trashcan, but i can't recall doing that. Are you sure you haven't just forgotten where you posted or had your topic moved to the correct section?
Posts dissappearing is only possible really if a mod deletes them, or if there's been a database rollback, and if it was the latter, everone would have lost posts. In my experience its usually either they were never posted, or they've lost their post.
I've "lost" my posts before, simply because i forgot where i posted them