ok, got it!
Thanks. I was surprised to see the error was the database connection, because I had edited the file supplied with all the correct information.
But that was the error, so I also noticed that in DW, the database connection was not recognized. When I recreated it, it didn't overwrite it, it created a new one; the old one was indented in the panel. I deleted it and tested the page successfully.
Thanks again. Any idea why code is also rewritten sometimes, when I open a page, in the PHP code? should I turn the feature off in the preferences? I like that when I paste things in the WYSIWYG panel it converts it for me.