You should rename classes12.zip to classes12.jar. I think JBoss will only find libs named *.jar
The class it's trying to load is the one from your config, but I agree it would be helpful to see.
You can check your startup log to make sure the driver file is loaded properly. I think the "doesn't load zip" was fixed a long time ago, but I don't have a zip file handy to try with.
Any chance there is extra whitespace around the driver class name?
I got the exact same problem. Have you found out why yet?
I am running jboss3rc2 on windows 2000.