It is reported when user runs NetBeans installer on Windows XP. I do not know if it depends on selected desktop theme or if user uses modified desktop theme.

Here is exception call stack:
java.lang.NullPointerException
        at com.sun.java.swing.plaf.windows.XPStyle.getString(XPStyle.java:132)
        at com.sun.java.swing.plaf.windows.XPStyle.getString(XPStyle.java:115)
        at com.sun.java.swing.plaf.windows.XPStyle.<init>(XPStyle.java:811)
        at com.sun.java.swing.plaf.windows.XPStyle.getXP(XPStyle.java:82)
        at com.sun.java.swing.plaf.windows.WindowsTreeUI$ExpandedIcon.<init>(WindowsTreeUI.java:103)
        at com.sun.java.swing.plaf.windows.WindowsTreeUI$ExpandedIcon.createExpandedIcon(WindowsTreeUI.java:107)
        at com.sun.java.swing.plaf.windows.WindowsLookAndFeel.initComponentDefaults(WindowsLookAndFeel.java:313)
        at javax.swing.plaf.basic.BasicLookAndFeel.getDefaults(BasicLookAndFeel.java:97)
        at javax.swing.UIManager.setLookAndFeel(UIManager.java:441)
        at javax.swing.UIManager.setLookAndFeel(UIManager.java:481)
        at com.installshield.wizard.swing.SwingWizardUI.switchToSystemLAF(Unknown Source)
        at com.installshield.wizard.swing.SwingWizardUI.initialize(Unknown Source)
        at com.installshield.wizard.StandardWizardListener.wizardInitializing(Unknown Source)
        at com.installshield.wizard.Wizard$WizardListenerInitializer.run(Unknown Source)
        at java.lang.Thread.run(Thread.java:595)

I corrected description. It is not from Windows Vista but Windows XP.