java.lang.NullPointerException
   at org.netbeans.modules.refactoring.php.findusages.WhereUsedElement.create(WhereUsedElement.java:207)
   at org.netbeans.modules.refactoring.php.findusages.WhereUsedSupport$Results.addEntry(WhereUsedSupport.java:326)
   at org.netbeans.modules.refactoring.php.findusages.WhereUsedSupport$Results.access$300(WhereUsedSupport.java:291)
   at org.netbeans.modules.refactoring.php.findusages.WhereUsedSupport.collectUsages(WhereUsedSupport.java:187)
   at org.netbeans.modules.refactoring.php.findusages.PhpWhereUsedQueryPlugin.prepare(PhpWhereUsedQueryPlugin.java:91)
   at org.netbeans.modules.refactoring.api.AbstractRefactoring.pluginsPrepare2(AbstractRefactoring.java:419)
   at org.netbeans.modules.refactoring.api.AbstractRefactoring.pluginsPrepare(AbstractRefactoring.java:403)
   at org.netbeans.modules.refactoring.api.AbstractRefactoring.prepare(AbstractRefactoring.java:218)
   at org.netbeans.modules.refactoring.spi.impl.ParametersPanel$Prepare.run(ParametersPanel.java:851)
   at org.openide.util.RequestProcessor$Task.run(RequestProcessor.java:1424)
   at org.openide.util.RequestProcessor$Processor.run(RequestProcessor.java:1968)