用JApplet and Batik開發SVG的問題

Dear All:
  我在applet中使用apache batik 開發SVG的時候遇到了如下問題:
  錯誤描述:
  java.lang.Exception
at org.apache.batik.swing.svg.GVTTreeBuilder.run(Unknown Source)
java控制台信息如下：
  java.lang.ExceptionInInitializerError
at org.apache.batik.css.parser.Parser.createScanner(Unknown Source)
at org.apache.batik.css.parser.Parser.parseStyleSheet(Unknown Source)
at org.apache.batik.css.engine.CSSEngine.parseStyleSheet(Unknown Source)
at org.apache.batik.css.engine.CSSEngine.parseStyleSheet(Unknown Source)
at org.apache.batik.dom.svg.SVGDOMImplementation.createCSSEngine(Unknown Source)
at org.apache.batik.dom.ExtensibleDOMImplementation.createCSSEngine(Unknown Source)
at org.apache.batik.bridge.BridgeContext.initializeDocument(Unknown Source)
at org.apache.batik.bridge.GVTBuilder.build(Unknown Source)
at org.apache.batik.swing.svg.GVTTreeBuilder.run(Unknown Source)
Caused by: java.lang.NullPointerException
at org.apache.batik.Version.getVersion(Unknown Source)
at org.apache.batik.util.ParsedURL.<clinit>(Unknown Source)
... 9 more
  麻煩各位高手指點.
  我在netBeans里面運行一點問題也沒有.但是布置到tomcat上就出現了這個問題.
  原代碼如下:
        svgCanvas.setDocumentState(JSVGCanvas.ALWAYS_DYNAMIC);
        svgCanvas.addSVGLoadEventDispatcherListener (
             new SVGLoadEventDispatcherAdapter () {
                @Override
               public void svgLoadEventDispatchStarted (
                     SVGLoadEventDispatcherEvent e) {
                window = svgCanvas.getUpdateManager ().
                     getScriptingEnvironment ().createWindow ();
              }
           });        
        DOMImplementation dom =SVGDOMImplementation.getDOMImplementation ();
        document = dom.createDocument ( SVGDOMImplementation.SVG_NAMESPACE_URI, "svg", null);
        try{
            svgCanvas.setDocument (document);     //在WEB上執行了這一句後就出了異常.
        }catch(Exception ex){            System.out.println(ex.toString());
        }