Help: Can't find js.jar

I am almost done implementing a batik plugin for eclipse. The last missing piece is support for dynamic updates. I am using JSVGCanvas and whenever I try to load an SVG file that contains a script I am getting this exception:

java.lang.NoClassDefFoundError: org/mozilla/_javascript_/NativeScript
        at java.lang.ClassLoader.defineClass0(Native Method)
        at java.lang.ClassLoader.defineClass(ClassLoader.java:502)
        at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:123)
        at org.apache.batik.script.rhino.RhinoClassLoader.defineClass(Unknown Source)
        at org.apache.batik.script.rhino.BatikSecuritySupport.defineClass(Unknown Source)
        at org.mozilla._javascript_.optimizer.Codegen.compile(Unknown Source)
        at org.mozilla._javascript_.Context.compile(Unknown Source)
        at org.mozilla._javascript_.Context.compile(Unknown Source)
        at org.mozilla._javascript_.Context.compileReader(Unknown Source)
        at org.mozilla._javascript_.Context.evaluateReader(Unknown Source)
        at org.apache.batik.script.rhino.RhinoInterpreter.evaluate(Unknown Source)
        at org.apache.batik.script.rhino.RhinoInterpreter.bindObject(Unknown Source)
        at org.apache.batik.bridge.BaseScriptingEnvironment.initializeEnvironment(Unknown Source)
        at org.apache.batik.bridge.BaseScriptingEnvironment.loadScripts(Unknown Source)
        at org.apache.batik.bridge.UpdateManager.dispatchSVGLoadEvent(Unknown Source)
        at org.apache.batik.swing.svg.SVGLoadEventDispatcher.run(Unknown Source)

Eclipse is using its own specialized classloader, so I am assuming it has something to do with that. The RhinoClassLoader class probably makes certain assumptes regarding the class loading procedure. Can anyone point me to the right direction?

--Dirk