Has anyone actually not gotten the error message when you've posted? It sounds as if all the rest of you have figured the way around it--which takes you back to the forum index. I've also discovered that simply clicking on the back arrows at the top of the page gets me to the thread and my post. Tony (and Jason) says the problem is "intermittent," but I have yet to have a post on any thread be submitted, and then show up properly on it's thread.
Edited to correct where you end up by clicking on Forum Index, and adding the other way of getting back to your post.
Wouldn't you know after complaining about this, I got straight through for the very first time (who knows what it'll do now).