SOLUTION!!! Anyone Experiencing a "Content Area Not Fount" message Should Read This
First a huge round of applause to Jason and the entire support team at WebAssist. They stuck with me through this frustrating problem until it was fixed.
If you've been following this thread, you've seen that I had PowerCMS working just fine on a computer; then I got a new computer and was unable to get it to work on the new one. I got the Database Connection to connect to the DB just fine, but the CMS content areas still reported "Content Area Not Found."
It turns out there's no problem at all with PowerCMS - the problem is with DREAMWEAVER! (Imagine that.) If you haven't encountered this yet, be aware: DW is hypersensitive to server setup - both remote and testing.
My setup is that I work directly on my remote server (I do not use WAMP or XAMPP), so my remote and my testing server need to be identical. If your setup is different, then your servers will be different.
In setting up my servers on my LINUX/APACHE host, I set the ROOT DIRECTORY field to public_html, as it should be. However, in the next field, WEB URL, I had appended /public_html to my website URL. THIS WAS WRONG. The Web URL should be only the web address of the host.
Nothing in Dreamweaver gives us any clue about what works here and what doesn't, and the two frustrating things about it are that sometimes you can enter the wrong things and it will still seem to work (but not with PowerCMS), and the Dreamweaver error messages are worse than no error messages at all.
Thanks to Jason's guidance, I got PowerCMS working again, and now know how to properly configure servers.
Again, hearty thanks to Jason and WebAssist.