NullPointer when setting class attribute of -tag

[Raphael Matter]

Hi,

i try to set the class-attribute of a use element in my EventListener, like:

public void handleEvent(Event evt) {
        Element target = (Element)evt.getCurrentTarget();
        target.setAttribute("class", classAttrib);   //Exception here!!!
    } }

..but i run into the following exception:

java.lang.NullPointerException
    at
org.apache.batik.bridge.SVGUseElementBridge.handleAnimatedAttributeChanged(SVGUseElementBridge.java:456)
    at
org.apache.batik.bridge.BridgeContext$AnimatedAttrListener.animatedAttributeChanged(BridgeContext.java:1763)
    at
org.apache.batik.dom.svg.SVGOMDocument$AnimAttrListener.animatedAttributeChanged(SVGOMDocument.java:706)
    at
org.apache.batik.dom.svg.AbstractSVGAnimatedValue.fireAnimatedAttributeListeners(AbstractSVGAnimatedValue.java:132)
    at
org.apache.batik.dom.svg.SVGOMAnimatedString.attrModified(SVGOMAnimatedString.java:115)
    at
org.apache.batik.dom.svg.AbstractElement.attrModified(AbstractElement.java:238)
    at
org.apache.batik.dom.AbstractElement.fireDOMAttrModifiedEvent(AbstractElement.java:627)
    at
org.apache.batik.dom.svg.AbstractElement.fireDOMAttrModifiedEvent(AbstractElement.java:117)
    at org.apache.batik.dom.AbstractAttr.setNodeValue(AbstractAttr.java:156)
    at org.apache.batik.dom.AbstractAttr.setValue(AbstractAttr.java:199)
    at
org.apache.batik.dom.AbstractElement.setAttribute(AbstractElement.java:144)
    at OnHoverAction.handleEvent(OnHoverAction.java:30)
    at
org.apache.batik.dom.events.EventSupport.fireEventListeners(EventSupport.java:324)
    at
org.apache.batik.dom.events.EventSupport.fireEventListeners(EventSupport.java:366)
    at
org.apache.batik.dom.events.EventSupport.dispatchEvent(EventSupport.java:276)
    at
org.apache.batik.dom.AbstractNode.dispatchEvent(AbstractNode.java:1014)
    at
org.apache.batik.bridge.BridgeEventSupport$Listener.dispatchMouseEvent(BridgeEventSupport.java:405)
    at
org.apache.batik.bridge.BridgeEventSupport$Listener.mouseEntered(BridgeEventSupport.java:266)
    at
org.apache.batik.gvt.event.AbstractAWTEventDispatcher.processMouseEvent(AbstractAWTEventDispatcher.java:592)
    at
org.apache.batik.gvt.event.AbstractAWTEventDispatcher.dispatchMouseEvent(AbstractAWTEventDispatcher.java:523)
    at
org.apache.batik.gvt.event.AbstractAWTEventDispatcher.dispatchEvent(AbstractAWTEventDispatcher.java:387)
    at
org.apache.batik.gvt.event.AbstractAWTEventDispatcher.mouseMoved(AbstractAWTEventDispatcher.java:210)
    at
org.apache.batik.swing.svg.AbstractJSVGComponent$1$MouseMovedRunnable.run(AbstractJSVGComponent.java:2248)
    at org.apache.batik.util.RunnableQueue.run(RunnableQueue.java:237)
    at java.lang.Thread.run(Unknown Source)

seems only  to happen for use-elements.
does anyboy know what could be wrong here?

thanks a lot
raphael