I've run into the same problem. First before posting remember to save your work. Then try to post. Even if you get this message, it will sometimes post anyway. Change the page and go back. Check your blog space and see if it posted or not. If it hasn't posted within ten minutes I just hit paste and resubmit my work, especially if it disappeared. Try that and see if it's not just some glitch. I've had success by simply ignoring the warnings, changing pages and looking at my posts. Most of the time it has posted anyway.