Danke, I do not really understand how to install an older version. My concern is that a complied previously working program (.jar) no longer works on our main office computer - the same message pops up. Does this mean all users need to install an earlier version of Java Development Kit than JDK 1.6.23? Respekt John Tripp

Hi I am also an learner with Jabaco. I am having the same message as copied below. I have tried to re-installing Java, upgrading, loading the developer and the error message does not go away. I complied the calculator sample provided with Jabaco, to make sure it was not my software, and it also generates the same message when being lloaded. I tested it on my XP sp3 dell notebook. My concern is the fixes suggested below (which do not work for me) will not be available to people who I have sent or...