After several weeks, I finally solved the problem. I got help from someone who'd had the problem previously. It was a problem with the Autofill setting's "Advanced" tab in the Tools menu. Netscape automatically fills in that tab, and I had to delete "subject" in that tab.

Before I solved the problem, I tried to find a contact address for ezboard. It's a waste of time. The site keeps suggesting questions from the FAQ that might help. Some sites make it very difficult to find a contact address, and when you do, many of them send you automatic emails, which are replies sent by a program, based on keywords in your email. I'm pretty sure Amazon.com uses them, because I've gotten emails from them with the exact same text in some paragraphs that I've had in others.

Thanks, anyway.