JBuilder - Cambio de version

Disculpen alguien me puede decir como puedo cambiar de version si estoy trabajando en jdk1.3.1 y la quiero pasar a jdk 1.4_2 devido a que tengo errores como estos:
java.lang.NullPointerException
at com.sun.java.swing.plaf.windows.WindowsRadioButtonUI.getPreferredSize(WindowsRadioButtonUI.java:97)
at javax.swing.plaf.basic.BasicButtonUI.getMinimumSize(BasicButtonUI.java:382)
at javax.swing.JComponent.getMinimumSize(JComponent.java:1359)
at javax.swing.BoxLayout.checkRequests(BoxLayout.java:428)
at javax.swing.BoxLayout.preferredLayoutSize(BoxLayout.java:246)
at java.awt.Container.preferredSize(Container.java:1178)
at java.awt.Container.getPreferredSize(Container.java:1162)
at javax.swing.JComponent.getPreferredSize(JComponent.java:1277)
at java.awt.GridBagLayout.GetLayoutInfo(GridBagLayout.java:892)
at java.awt.GridBagLayout.getLayoutInfo(GridBagLayout.java:806)
at java.awt.GridBagLayout.preferredLayoutSize(GridBagLayout.java:630)
at java.awt.Container.preferredSize(Container.java:1178)
at java.awt.Container.getPreferredSize(Container.java:1162)
at javax.swing.JComponent.getPreferredSize(JComponent.java:1277)
at java.awt.BorderLayout.layoutContainer(BorderLayout.java:668)
at java.awt.Container.layout(Container.java:1020)
at java.awt.Container.doLayout(Container.java:1010)
at java.awt.Container.validateTree(Container.java:1092)
at java.awt.Container.validateTree(Container.java:1099)
at java.awt.Container.validateTree(Container.java:1099)
at java.awt.Container.validateTree(Container.java:1099)
at java.awt.Container.validateTree(Container.java:1099)
at java.awt.Container.validateTree(Container.java:1099)
at java.awt.Container.validateTree(Container.java:1099)
at java.awt.Container.validate(Container.java:1067)
at javax.swing.RepaintManager.validateInvalidComponents(RepaintManager.java:353)
at javax.swing.SystemEventQueueUtilities$ComponentWorkRequest.run(SystemEventQueueUtilities.java:116)
at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:178)
at java.awt.EventQueue.dispatchEvent(EventQueue.java:454)
at java.awt.EventDispatchThread.pumpOneEventForHierarchy(EventDispatchThread.java:201)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:151)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:145)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:137)
at java.awt.EventDispatchThread.run(EventDispatchThread.java:100)