NetBeans IDE Dev (Build 200608261800)
1.5.0_05; Java HotSpot(TM) Client VM 1.5.0_05-b05
Windows XP version 5.1 running on x86
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At project or file explorer,
right click on any folder -> new folder

Let the name of new folder to be created is zebra.
Specify the parent folder to have invalid XP filename characters like "z:\zoo",
so that the full path of new folder is something like,
"C:\Crappy Projects\Example\WebRoot\z:\zoo\zebra".

Clicking on finish would result in Exception window.
I think it is emotionally less traumatic to the programmer to encounter
a window that says,
"Illegal parent folder specified" or
"Illegal file name specified"

rather than a frightening exception window like this.
(Exception windows are always frightening and traumatic - 
"exception encountered traumatic syndrome"):

java.lang.IllegalArgumentException: Called DataObject.find on null
	at org.openide.loaders.DataObject.find(DataObject.java:445)
	at org.openide.loaders.DataFolder.findFolder(DataFolder.java:485)
	at 
org.netbeans.spi.project.ui.templates.support.Templates.setTargetFolder
(Templates.java:133)
	at 
org.netbeans.modules.project.ui.SimpleTargetChooserPanel.storeSettings
(SimpleTargetChooserPanel.java:168)
	at org.openide.WizardDescriptor.setValue(WizardDescriptor.java:1128)
	at 
org.netbeans.core.windows.services.NbPresenter$ButtonListener.actionPerformed
(NbPresenter.java:1026)