When you've had a browser window up for a long time while writing a post, the page will time out and give you an error message when you try to submit. Usually hitting the "Back" button on the browser and then hitting "Submit" again will fix it, but some browsers may not preserve your text. I don't usually have that problem using Chrome, but before hitting Submit, I always do a block copy on long posts anyway. That way if the page crashes, I can just paste the text back in. I know that won't help you this time, but FYI for you and others.