Custom UNO script provider throwing "Bad insert element" error.

I’m writing a script provider for Scala, using the Java helper classes as described here, but I get the message “Bad insert element” when I try to add it with the extension manager. Either IntelliJ or 7-zip is packaging it funny, because if I recompress it in 7-zip I instead get “com.sun.star.registry.CannotRegisterImplementationException: Cannot determine registration class!” as the error message.

I’ve added jurt.jar, unoil.jar, ridl.jar, and ScriptFramework.jar to the classpath, and I’ve tried it both with my dependencies packaged in my jar and linked externally. One post I saw said my class had to have the form “com.sun.star.script.provider.ScriptProviderFor[Language]” so I did that.

Alternately, if there’s already Scala support that I missed, that would be even better.