In the Lute-list Gernot Hilger gave this advice to Mac-users: ------------------------------------------------------------ (3.4.2006) Hi Mac-users, I also had some trouble with the calculator. Here's how to get it to work under 10.4.5 - load the J2SE5 Java package from www.apple.com (a hefty 42 MB download) - install Java 5 aka 1.5 - open Java Preferences - select "General" tab - activate J2SE 5.0 - drag J2SE 5.0 to the top in Java Application Runtime Settings I had deleted the temporary files, whether this was necessary or not, I don't know. Good luck Gernot