Your submission could not be processed because the token has expired.

Huh?

I typed up a nice informative post and clicked the 'go advanced' button so I could proofread it and it gave me that error. So I clicked the back button on the browser and my entire post was gone. No way to salvage was I had just spent quite a bit of time working on.

I don't understand the point of this. Is it set to 'timeout' after a certain amount of time? Why? What if a poo sneaks up on me as I'm typing up a post?