After painstakingly composing a message to another registered member, and beginning with an appropriate heading, a box keeps appearing informing me that I have to have a heading, which I have, and then a body to my message, which I also have, but/or won't allow me to submit it. I hate the thought of losing such a carefully worded and sincere message to someone. What's up with this?

Have had the same thing happen too. Seems to just be a system flaw that crops up sometimes. Try highlighting your message, right click and copy it, then open a new message, paste your text in the new box, and try sending it again. Still a bit of a pain, but less trouble than having to retype it all.