The Plugin installs successfully, but it will not load when I come to an .html page with an embedded ChemDraw document. All I see is a puzzle piece.
First, check to see if you have more than one version of the ChemDraw Plugin intalled. You can determine this by opening the Add/Remove control panel, and checking the list for ChemDraw Plugins. Try uninstalling any ChemDraw Plugins in this list. After uninstalling, restart your computer, reinstall the ChemDraw Plugin, and retest the problem. If this does not help, save any Bookmarks, Favorites, and Address Books associated with your web browser. Uninstall or delete your web browser, and the ChemDraw Plugin. Reinstall your web browser, and then the ChemDraw Plugin.
Another possibility is that you are opening an html page with embedded ChemDraw structures that is not being served by a webserver (i.e. your opening a page that is on your hard drive or file server). Webservers have a mime-type mapping table somewhere, which converts extension or filetype to mime-type so they can specify the right Content-type: header in the http reply. When reading a file, this has to come from somewhere else. On Windows, there's a place in the registry that IE uses, but Netscape doesn't. However, it does have a helper applications table in its preferences dialog, which might be able to supply a mapping for file type or extension to mime-type.