java.lang.NoClassDefFoundError: Could not initialize class org.whattf.checker.NormalizationChecker
   at nu.validator.messages.MessageEmitterAdapter.scrub(MessageEmitterAdapter.java:377)
   at nu.validator.messages.MessageEmitterAdapter.emitStringWithQurlyQuotes(MessageEmitterAdapter.java:1068)
   at nu.validator.messages.MessageEmitterAdapter.messageText(MessageEmitterAdapter.java:817)
   at nu.validator.messages.MessageEmitterAdapter.messageWithoutExtract(MessageEmitterAdapter.java:799)
   at nu.validator.messages.MessageEmitterAdapter.message(MessageEmitterAdapter.java:730)
   at nu.validator.messages.MessageEmitterAdapter.internalError(MessageEmitterAdapter.java:561)
   at org.netbeans.modules.html.validation.ValidationTransaction.validate(ValidationTransaction.java:641)
   at org.netbeans.modules.html.validation.ValidationTransaction.validateCode(ValidationTransaction.java:473)
   at org.netbeans.modules.html.validation.ValidatorImpl.validate(ValidatorImpl.java:120)
   at org.netbeans.modules.html.editor.api.gsf.HtmlParserResult.getErrorsFromValidatorService(HtmlParserResult.java:301)
   at org.netbeans.modules.html.editor.api.gsf.HtmlParserResult.getValidationResults(HtmlParserResult.java:278)
   at org.netbeans.modules.html.editor.api.gsf.HtmlParserResult.getDiagnostics(HtmlParserResult.java:267)
   at org.netbeans.modules.html.editor.hints.HtmlRuleContext.<init>(HtmlRuleContext.java:84)
   at org.netbeans.modules.html.editor.hints.HtmlHintsProvider.computeErrors(HtmlHintsProvider.java:255)
   at org.netbeans.modules.csl.hints.GsfHintsProvider.processProviderErrors(GsfHintsProvider.java:321)
   at org.netbeans.modules.csl.hints.GsfHintsProvider.processErrors(GsfHintsProvider.java:407)
   at org.netbeans.modules.csl.hints.GsfHintsProvider.processErrorsRecursive(GsfHintsProvider.java:383)
   at org.netbeans.modules.csl.hints.GsfHintsProvider.processErrorsRecursive(GsfHintsProvider.java:378)
   at org.netbeans.modules.csl.hints.GsfHintsProvider.refreshErrors(GsfHintsProvider.java:351)
   at org.netbeans.modules.csl.hints.GsfHintsProvider.access$000(GsfHintsProvider.java:101)
   at org.netbeans.modules.csl.hints.GsfHintsProvider$2.run(GsfHintsProvider.java:434)
   at org.netbeans.modules.parsing.impl.TaskProcessor.callUserTask(TaskProcessor.java:593)
   at org.netbeans.modules.parsing.api.ParserManager$UserTaskAction.run(ParserManager.java:155)
   at org.netbeans.modules.parsing.api.ParserManager$UserTaskAction.run(ParserManager.java:139)
   at org.netbeans.modules.parsing.impl.TaskProcessor$2.call(TaskProcessor.java:206)
   at org.netbeans.modules.parsing.impl.TaskProcessor$2.call(TaskProcessor.java:203)
   at org.netbeans.modules.masterfs.filebasedfs.utils.FileChangedManager.priorityIO(FileChangedManager.java:176)
   at org.netbeans.modules.masterfs.providers.ProvidedExtensions.priorityIO(ProvidedExtensions.java:360)
   at org.netbeans.modules.parsing.impl.Utilities.runPriorityIO(Utilities.java:74)
   at org.netbeans.modules.parsing.impl.TaskProcessor.runUserTask(TaskProcessor.java:203)
   at org.netbeans.modules.parsing.api.ParserManager.parse(ParserManager.java:106)
   at org.netbeans.modules.csl.hints.GsfHintsProvider.run(GsfHintsProvider.java:432)
   at org.netbeans.modules.csl.hints.GsfHintsProvider.run(GsfHintsProvider.java:101)
   at org.netbeans.modules.parsing.impl.TaskProcessor.callParserResultTask(TaskProcessor.java:568)
   at org.netbeans.modules.parsing.impl.TaskProcessor$CompilationJob.run(TaskProcessor.java:744)
   at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:471)
   at java.util.concurrent.FutureTask.run(FutureTask.java:262)
   at org.openide.util.RequestProcessor$Task.run(RequestProcessor.java:1423)
   at org.openide.util.RequestProcessor$Processor.run(RequestProcessor.java:2033)