I found that, for some reason, previewing SimpleViewer in Dreamweaver doesn't seem to work. I had to upload the files to a server to see the results.
And if you are trying to embed your SimpleViewer in an existing page, rather than have it as a stand-alone page, how you organize the files is critical. I got it to work with two approaches:
One is, if the page you have embedded SimpleViewer in is in your root level, once you have the SimpleViewer XML set up for your images, move the files and images and thumbs folders (except index.html), out of the SimpleViewer folder into the root level. Then your url can point directly to your page with SimpleViewer embedded. You no longer need the SimpleViewer folder or the index.html that was in that folder on your server.
The other way to organize the files, is to move your file with SimpleViewer embedded in it into the SimpleViewer folder, and remove the index.html file that was in that SimpleViewer folder. Then you may want to rename the SimpleViewer folder.
For example, let's say your website is at www.coinsforall.biz, you created your web page with SimpleViewer embedded in it to display photos of coins, and you named that page coins.html. You could rename the SimpleViewer folder to "coins", put your web page in that folder, and your url to the page would be: http://www.coinsforall.biz/coins/coins.html.