Erro jtable

Colegas,
quando meu frmUser abre da o seguinte erro:

 17/01/2011 21:42:08 br.com.devmedia.completeswingapp.frames.MyTableModel
SEVERE: null
java.lang.NullPointerException
        at br.com.devmedia.completeswingapp.frames.MyTableModel.startAddValues(MyTableModel.java:70)
        at br.com.devmedia.completeswingapp.frames.MyTableModel.(MyTableModel.java:45)
        at br.com.devmedia.completeswingapp.frames.frmUsers.loadInitialData(frmUsers.java:199)
        at br.com.devmedia.completeswingapp.frames.frmUsers.(frmUsers.java:31)
        at br.com.devmedia.completeswingapp.frames.frmPrincipal.jButton1ActionPerformed(frmPrincipal.java:191)
        at br.com.devmedia.completeswingapp.frames.frmPrincipal.access$000(frmPrincipal.java:23)
        at br.com.devmedia.completeswingapp.frames.frmPrincipal$1.actionPerformed(frmPrincipal.java:71)
        at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:2012)
        at javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2335)
        at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:404)
        at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:259)
        at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(BasicButtonListener.java:253)
        at java.awt.Component.processMouseEvent(Component.java:6175)
        at javax.swing.JComponent.processMouseEvent(JComponent.java:3267)
        at java.awt.Component.processEvent(Component.java:5940)
        at java.awt.Container.processEvent(Container.java:2105)
        at java.awt.Component.dispatchEventImpl(Component.java:4536)
        at java.awt.Container.dispatchEventImpl(Container.java:2163)
        at java.awt.Component.dispatchEvent(Component.java:4362)
        at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4461)
        at java.awt.LightweightDispatcher.processMouseEvent(Container.java:4125)
        at java.awt.LightweightDispatcher.dispatchEvent(Container.java:4055)
        at java.awt.Container.dispatchEventImpl(Container.java:2149)
        at java.awt.Window.dispatchEventImpl(Window.java:2478)
        at java.awt.Component.dispatchEvent(Component.java:4362)
        at java.awt.EventQueue.dispatchEvent(EventQueue.java:604)
        at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:275)
        at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:200)
        at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:190)
        at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:185)
        at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:177)
        at java.awt.EventDispatchThread.run(EventDispatchThread.java:138)


O que posso fazer para resolver?
Obrigado mais uma vez!

Quando clico em built project recebo essa mensagem:
Note: /home/nsouza/NetBeansProjects/teste/MyCompleteSwingApp/src/br/com/devmedia/completeswingapp/frames/MyTableModel.java uses unchecked or unsafe operations.
Note: Recompile with -Xlint:unchecked for details.
Copying 13 files to /home/nsouza/NetBeansProjects/teste/MyCompleteSwingApp/build/classes
compile:
Created dir: /home/nsouza/NetBeansProjects/teste/MyCompleteSwingApp/dist
Copy libraries to /home/nsouza/NetBeansProjects/teste/MyCompleteSwingApp/dist/lib.
Building jar: /home/nsouza/NetBeansProjects/teste/MyCompleteSwingApp/dist/MyCompleteSwingApp_nilo.jar
To run this application from the command line without Ant, try:
java -jar "/home/nsouza/NetBeansProjects/teste/MyCompleteSwingApp/dist/MyCompleteSwingApp_nilo.jar"