Up the Sync
Up the Sync requires the latest version of Java to run. If you don't have this version installed or you are unsure, you can download it from here.
Mac users may have to change their Java preferences. It requires Java 1.6 to run. Open "Java Preferences" in the Utilites folder in Applications.
Under the "General" tab make sure "Java SE 6" is selected and at the top of the list (click and drag it to the top).
If this doesn't solve your problem feel free to contact the developer.