java.lang.NullPointerException
        at com.sun.org.apache.xerces.internal.impl.XMLEntityScanner.skipChar(XMLEntityScanner.java:1414)
        at com.sun.org.apache.xerces.internal.impl.XMLDTDScannerImpl.skipSeparator(XMLDTDScannerImpl.java:2056)
        at com.sun.org.apache.xerces.internal.impl.XMLDTDScannerImpl.scanDecls(XMLDTDScannerImpl.java:2031)
        at com.sun.org.apache.xerces.internal.impl.XMLDTDScannerImpl.scanDTDExternalSubset(XMLDTDScannerImpl.java:320)
        at com.sun.org.apache.xerces.internal.impl.XMLDocumentScannerImpl$DTDDriver.dispatch(XMLDocumentScannerImpl.java:1185)
        at com.sun.org.apache.xerces.internal.impl.XMLDocumentScannerImpl$DTDDriver.next(XMLDocumentScannerImpl.java:1075)
        at com.sun.org.apache.xerces.internal.impl.XMLDocumentScannerImpl$PrologDriver.next(XMLDocumentScannerImpl.java:993)
        at com.sun.org.apache.xerces.internal.impl.XMLDocumentScannerImpl.next(XMLDocumentScannerImpl.java:647)
        at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl.scanDocument(XMLDocumentFragmentScannerImpl.java:508)
        at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(XML11Configuration.java:807)
        at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(XML11Configuration.java:737)
        at com.sun.org.apache.xerces.internal.parsers.XMLParser.parse(XMLParser.java:107)
        at com.sun.org.apache.xerces.internal.parsers.AbstractSAXParser.parse(AbstractSAXParser.java:1205)
        at com.sun.org.apache.xerces.internal.jaxp.SAXParserImpl$JAXPSAXParser.parse(SAXParserImpl.java:522)
        at org.netbeans.modules.xml.dtd.grammar.DTDParser.parse(DTDParser.java:115)
        at org.netbeans.modules.xml.dtd.grammar.DTDGrammarQueryProvider.getGrammar(DTDGrammarQueryProvider.java:73)
        at org.netbeans.modules.xml.api.model.GrammarQueryManager$DefaultQueryManager.getGrammar(GrammarQueryManager.java:148)
        at org.netbeans.modules.xml.text.completion.GrammarManager.loadGrammar(GrammarManager.java:313)
        at org.netbeans.modules.xml.text.completion.GrammarManager.getGrammar(GrammarManager.java:130)
        at org.netbeans.modules.xml.text.completion.XMLCompletionQuery.getPerformer(XMLCompletionQuery.java:300)
        at org.netbeans.modules.xml.text.completion.XMLCompletionQuery.queryValues(XMLCompletionQuery.java:333)
        at org.netbeans.modules.xml.text.completion.XMLCompletionQuery.query(XMLCompletionQuery.java:136)
        at org.netbeans.modules.xml.text.completion.XMLCompletionProvider$Query.doQuery(XMLCompletionProvider.java:110)
        at org.netbeans.modules.xml.text.completion.XMLCompletionProvider$Query.query(XMLCompletionProvider.java:127)
        at org.netbeans.spi.editor.completion.support.AsyncCompletionTask.run(AsyncCompletionTask.java:218)
        at org.openide.util.RequestProcessor$Task.run(RequestProcessor.java:561)
        at org.openide.util.RequestProcessor$Processor.run(RequestProcessor.java:986)