Seen with NetBeans 6.7.1.

1. Create a new WSDL document that contains at least one message. An example is
attached.

2. In the WSDL view of the WSDL editor, delete a message.

3. Click the Refactor button in the dialog.

4. An error dialog pops up with the following error message:

java.lang.NullPointerException
	at
org.netbeans.modules.xml.wsdl.refactoring.WSDLWhereUsedRefactoringPlugin.prepare(WSDLWhereUsedRefactoringPlugin.java:134)
	at org.netbeans.modules.refactoring.api.AbstractRefactoring.pluginsPrepare2(AbstractRefactoring.java:419)
	at org.netbeans.modules.refactoring.api.AbstractRefactoring.pluginsPrepare(AbstractRefactoring.java:403)
	at org.netbeans.modules.refactoring.api.AbstractRefactoring.prepare(AbstractRefactoring.java:214)
	at
org.netbeans.modules.xml.schema.refactoring.SchemaSafeDeleteRefactoringPlugin.prepare(SchemaSafeDeleteRefactoringPlugin.java:171)
	at org.netbeans.modules.refactoring.api.AbstractRefactoring.pluginsPrepare2(AbstractRefactoring.java:419)
	at org.netbeans.modules.refactoring.api.AbstractRefactoring.pluginsPrepare(AbstractRefactoring.java:403)
	at org.netbeans.modules.refactoring.api.AbstractRefactoring.prepare(AbstractRefactoring.java:214)
	at org.netbeans.modules.refactoring.spi.impl.ParametersPanel$Prepare.run(ParametersPanel.java:802)
	at org.openide.util.RequestProcessor$Task.run(RequestProcessor.java:577)
[catch] at org.openide.util.RequestProcessor$Processor.run(RequestProcessor.java:1030)

(If the dialog doesn't pop up, there is a red icon flashing in the lower-right-hand corner; click it to see the message.
Also, the errors are written to the log file.)

There are actually multiple NPEs, and the log is attached.