Apologies in advance but I have never seen this error before and don't know what to include. I am using NetBeans and suddenly began getting this error:

Exception in thread "AWT-EventQueue-0" java.lang.VerifyError: (class: market/CostOperations, method: <init> signature: ()V) Constructor must call super() or this()
            at Bluebuild.Main.refreshTables(Main.java:748)
            at Bluebuild.Main.formComponentShown(Main.java:649)
            at Bluebuild.Main.access$100(Main.java:28)
            at Bluebuild.Main$2.componentShown(Main.java:374)
            at java.awt.Component.processComponentEvent(Component.java:6095)
            at java.awt.Component.processEvent(Component.java:6043)
            at java.awt.Container.processEvent(Container.java:2041)
            at java.awt.Window.processEvent(Window.java:1836)
            at java.awt.Component.dispatchEventImpl(Component.java:4630)
            at java.awt.Container.dispatchEventImpl(Container.java:2099)
            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 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)

I have not a clue what happened. I didn't even modify market/CostOperations.

Here's the constructor though:

public CostOperations() throws ParserConfigurationException, SAXException, IOException {

        //Open the xml file
        DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
        DocumentBuilder builder = factory.newDocumentBuilder();
        f = new File(dbName);
        doc = builder.parse(f);
        System.out.println(f.canWrite());

        //Create the XPath
        XPathFactory xpfactory = XPathFactory.newInstance();
        path = xpfactory.newXPath();

    }

In Debug Mode I get this:

debug:
Have no FileObject for C:\Program Files (x86)\Java\jdk1.6.0_20\jre\lib\sunrsasign.jar
Have no FileObject for C:\Program Files (x86)\Java\jdk1.6.0_20\jre\classes

I just need to know what is causing the error and how to fix it. Thanks!