Fehler - RC startet nicht über webstart auf Vista unter Java 6

Code:
JNLPException[category: Launch File Error : Exception: null : LaunchDesc: 
<jnlp spec="1.5+" codebase="http://www.routeconverter.de/download/" href="http://www.routeconverter.de/routeconverter/launch">
  <information>
    <title>RouteConverter</title>
    <vendor>Christian Pesch</vendor>
    <homepage href="http://www.routeconverter.com"/>
    <description>RouteConverter shows, converts and edits GPS data in over 50 formats.</description>
    <description kind="short">RouteConverter converts GPS data to over 50 formats.</description>
    <description kind="tooltip">RouteConverter</description>
    <icon href="http://www.routeconverter.de/images/routeconverter32x32.gif" height="32" width="32" kind="default"/>
    <icon href="http://www.routeconverter.de/images/routeconverter64x64.gif" height="64" width="64" kind="default"/>
    <icon href="http://www.routeconverter.de/images/routeconverter256x256.png" height="256" width="256" kind="splash"/>
    <shortcut online="true">
      <menu submenu="RouteConverter"/>
    </shortcut>
    <association extensions="gpx" mime-type="application/x-gpx+xml"/>
    <association extensions="itn" mime-type="application/x-itn"/>
    <association extensions="ov2" mime-type="application/x-ov2"/>
    <offline-allowed/>
  </information>
  <security>
    <all-permissions/>
  </security>
  <update check="timeout" policy="always"/>
  <resources>
    <java max-heap-size="268435456" version="1.6+"/>
    <jar href="http://www.routeconverter.de/download/webstart/RouteConverterWebstart.jar" download="eager" main="false"/>
    <jar href="http://www.routeconverter.de/download/webstart/win32.win32.x86-3.6M6-stripped.jar" download="eager" main="false"/>
    <jar href="http://www.routeconverter.de/download/webstart/win32.win32.x86-1.3.6.jar" download="eager" main="false"/>
  </resources>
  <application-desc main-class="slash.navigation.converter.gui.RouteConverter6"/>
</jnlp> ]
	at com.sun.javaws.LaunchDownload.checkSignedResourcesHelper(Unknown Source)
	at com.sun.javaws.LaunchDownload.checkSignedResources(Unknown Source)
	at com.sun.javaws.Launcher.prepareResources(Unknown Source)
	at com.sun.javaws.Launcher.prepareAllResources(Unknown Source)
	at com.sun.javaws.Launcher.prepareToLaunch(Unknown Source)
	at com.sun.javaws.Launcher.prepareToLaunch(Unknown Source)
	at com.sun.javaws.Launcher.launch(Unknown Source)
	at com.sun.javaws.Main.launchApp(Unknown Source)
	at com.sun.javaws.Main.continueInSecureThread(Unknown Source)
	at com.sun.javaws.Main$1.run(Unknown Source)
	at java.lang.Thread.run(Unknown Source)