java.lang.AssertionError: D:\Java\sdk\jdk1.6.0_18\jre\bin\java exists and it's executable.
   at org.netbeans.modules.derby.RegisterDerby.start(RegisterDerby.java:275)
   at org.netbeans.modules.derby.RegisterDerby.ensureStarted(RegisterDerby.java:434)
   at org.netbeans.modules.derby.StartAction.performAction(StartAction.java:76)
   at org.openide.util.actions.CallableSystemAction$1.run(CallableSystemAction.java:126)
   at org.openide.util.actions.ActionInvoker$1.run(ActionInvoker.java:92)
   at org.openide.util.actions.ActionInvoker$ActionRunnable.actionPerformed(ActionInvoker.java:159)
   at org.netbeans.core.ModuleActions.invokeAction(ModuleActions.java:106)
   at org.netbeans.modules.openide.actions.ActionsBridgeImpl.invokeAction(ActionsBridgeImpl.java:57)
   at org.openide.util.actions.ActionInvoker$ActionRunnable.doRun(ActionInvoker.java:150)
   at org.openide.util.actions.ActionInvoker$2.run(ActionInvoker.java:107)
   at org.openide.util.RequestProcessor$Task.run(RequestProcessor.java:1356)
   at org.openide.util.RequestProcessor$Processor.run(RequestProcessor.java:1894)
Caused: org.openide.util.RequestProcessor$SlowItem: task failed due to: java.lang.AssertionError: D:\Java\sdk\jdk1.6.0_18\jre\bin\java exists and it's executable.
   at org.openide.util.RequestProcessor.post(RequestProcessor.java:355)
   at org.openide.util.actions.ActionInvoker.doPerformAction(ActionInvoker.java:111)
   at org.openide.util.actions.ActionInvoker.invokeAction(ActionInvoker.java:96)
   at org.openide.util.actions.CallableSystemAction.actionPerformed(CallableSystemAction.java:123)
   at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:1995)
   at javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2318)
   at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:387)
   at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:242)
   at javax.swing.AbstractButton.doClick(AbstractButton.java:357)
   at javax.swing.plaf.basic.BasicMenuItemUI.doClick(BasicMenuItemUI.java:1225)
   at javax.swing.plaf.basic.BasicMenuItemUI$Handler.mouseReleased(BasicMenuItemUI.java:1266)
   at java.awt.Component.processMouseEvent(Component.java:6263)
   at javax.swing.JComponent.processMouseEvent(JComponent.java:3267)
   at java.awt.Component.processEvent(Component.java:6028)
   at java.awt.Container.processEvent(Container.java:2041)
   at java.awt.Component.dispatchEventImpl(Component.java:4630)
   at java.awt.Container.dispatchEventImpl(Container.java:2099)
   at java.awt.Component.dispatchEvent(Component.java:4460)
   at java.awt.LightweightDispatcher.retargetMouseEvent(LightweightDispatcher.java:4574)
   at java.awt.LightweightDispatcher.processMouseEvent(LightweightDispatcher.java:4238)
   at java.awt.LightweightDispatcher.dispatchEvent(LightweightDispatcher.java:4168)
   at java.awt.Container.dispatchEventImpl(Container.java:2085)
   at java.awt.Window.dispatchEventImpl(Window.java:2478)
   at java.awt.Component.dispatchEvent(Component.java:4460)
   at java.awt.EventQueue.dispatchEvent(EventQueue.java:599)
   at org.netbeans.core.TimableEventQueue.dispatchEvent(TimableEventQueue.java:131)
   at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:269)
   at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:184)
   at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:174)
   at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:169)
   at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:161)
   at java.awt.EventDispatchThread.run(EventDispatchThread.java:122)