[ubuntu-it] jnpl

[luciopineda]

Ciao ho bisogno di aprire un file jnpl
da questo https://www.prorealtime.com/it/
in passato ero riuscito allo scopo seguendo
http://wiki.ubuntu-it.org/Programmazione/Java?action=show&redirect=InstallazioneJava
Ora usando open java non riesco più.
Quando lancio ,il programma o il file, viene caricato ma non lo 
visualizzo e mi da il seguente errore
net.sourceforge.jnlp.LaunchException: Fatal: Initialization Error: Could 
not initialize application.
     at net.sourceforge.jnlp.Launcher.createApplication(Launcher.java:778)
     at net.sourceforge.jnlp.Launcher.launchApplication(Launcher.java:552)
     at net.sourceforge.jnlp.Launcher$TgThread.run(Launcher.java:889)
Caused by: net.sourceforge.jnlp.LaunchException: Fatal: Application 
Error: Unknown Main-Class. Could not determine the main class for this 
application.
     at 
net.sourceforge.jnlp.runtime.JNLPClassLoader.initializeResources(JNLPClassLoader.java:508)
     at 
net.sourceforge.jnlp.runtime.JNLPClassLoader.<init>(JNLPClassLoader.java:201)
     at 
net.sourceforge.jnlp.runtime.JNLPClassLoader.getInstance(JNLPClassLoader.java:320)
     at net.sourceforge.jnlp.Launcher.createApplication(Launcher.java:770)
     ... 2 more
Caused by:
net.sourceforge.jnlp.LaunchException: Fatal: Application Error: Unknown 
Main-Class. Could not determine the main class for this application.
     at 
net.sourceforge.jnlp.runtime.JNLPClassLoader.initializeResources(JNLPClassLoader.java:508)
     at 
net.sourceforge.jnlp.runtime.JNLPClassLoader.<init>(JNLPClassLoader.java:201)
     at 
net.sourceforge.jnlp.runtime.JNLPClassLoader.getInstance(JNLPClassLoader.java:320)
     at net.sourceforge.jnlp.Launcher.createApplication(Launcher.java:770)
     at net.sourceforge.jnlp.Launcher.launchApplication(Launcher.java:552)
     at net.sourceforge.jnlp.Launcher$TgThread.run(Launcher.java:889)
Secondo voi come si può risolvere ?
Grazie