RCP with Wevstart

[SirWayne]

Hello community,

I have a problem to start my rcp via webstart.
I get follow error message in myLogfile

java.lang.NullPointerException
   at java.util.Hashtable.put(Unknown Source)
   at org.eclipse.core.launcher.WebStartMain.basicRun(WebStartMain.java:58)
   at org.eclipse.core.launcher.Main.run(Main.java:977)
   at org.eclipse.core.launcher.WebStartMain.main(WebStartMain.java:40)
   at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
   at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
   at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
   at java.lang.reflect.Method.invoke(Unknown Source)
   at com.sun.javaws.Launcher.executeApplication(Unknown Source)
   at com.sun.javaws.Launcher.executeMainClass(Unknown Source)
   at com.sun.javaws.Launcher.doLaunchApp(Unknown Source)
   at com.sun.javaws.Launcher.run(Unknown Source)
   at java.lang.Thread.run(Unknown Source)