Hello Victor,
You can try capturing a more meaningful error message. See http://scn.sap.com/community/developer-center/powerbuilder/blog/2014/09/24/how-to-capture-error-messages-from-an-activex-control.
Also one thing it could be is that java is not being found. Try putting the full path to java in your statement, for example: [path to java]\java -jar...
Ted Zimmerman