Figured it out! techfury, the problem is that WaMCom has a very old oji plugin and I never noticed before. 9.2.1 will include the updated MRJ plugin, but you can get it yourself:

http://www-archive.mozilla.org/oji/MRJPlugin.html

You should make sure you are running MRJ 2.2.4 first (download it from Apple if you don't know). Assuming that you are, drop the Netscape 6 plugins into your Plug-ins folder and restart Classilla. Note that you need both plugins and Java on for this to work, but it does indeed work.

Thanks for discovering this :I