So, create a unique Login ID for this individual account. Make sure that your login info for the Add on domain is NOT the same as your master FTP account.
For our purposes, we don't want to use the standard options. We want to create unique FTP accounts for the domain or sub-domain just created. This will allow the prospective webmaster access to only that domain.
Bluehost had exactly what I needed. This is how basic I am; I started by looking for what WordPress recommended, a fantastico logo that is a blue smiley face. They also wanted to make sure they had what is called cPanel.
OK, now that you have your domain hosted with a reputable host you are ready to install you blog. If you went with Bluehost you will simply log into your account and click on the WordPress icon and follow the simple directions to install your blog.
On the left panel, under the Appearance tab, click on Themes, click on Install Themes tab across the top, tick the boxes you want or put in name of a design or word and click Find Themes. Once you have found and settled on a theme, click Install, and then click Install Now button, then click Activate and your theme or design should be live on your website now.
So I fixed the problem. My home page is a new page that looks just like the old page but loads quickly and has no error box when I try to read more edit it. The lesson here is twofold: 1. copy your files regularly and be orderly about that. 2. Don't freak out. Usually there is a fix. Often the fix is fairly easy, as it was here.