Following build step failed:
Type: NUnit Report
Source Dir: testdotnet/reports
Files to process: *.xml

Whole BuildStep log:
13:08:36,8 [publish-report-tests-nunit@lab9:8811] INFO - Running step 'publish-report-tests-nunit' on node 'lab9:8811'...
13:08:36,8 [publish-report-tests-nunit@lab9:8811] INFO - Acquiring workspace mutex...
13:08:36,8 [publish-report-tests-nunit@lab9:8811] INFO - Workspace mutex acquired.
13:08:36,8 [publish-report-tests-nunit@lab9:8811] INFO - Start generating report 'tests'.
13:08:37,1 [publish-report-tests-nunit@lab9:8811] ERROR - Step 'publish-report-tests-nunit' is failed.
    com.pmease.quickbuild.plugin.report.engine.exception.ReportGenerateException: Executing rule 'Type: XPATH, Column: duration' failed.
        at com.pmease.quickbuild.plugin.report.engine.generator.AbstractProcessor.executeRule(AbstractProcessor.java:127)
        at com.pmease.quickbuild.plugin.report.engine.generator.xpath.XPathProcessor.processResource(XPathProcessor.java:91)
        at com.pmease.quickbuild.plugin.report.engine.generator.AbstractProcessor.doExecute(AbstractProcessor.java:74)
        at com.pmease.quickbuild.plugin.report.engine.generator.GenerateAction.execute(GenerateAction.java:37)
        at com.pmease.quickbuild.plugin.report.engine.generator.AbstractGenerator.doExecute(AbstractGenerator.java:38)
        at com.pmease.quickbuild.plugin.report.engine.generator.GenerateAction.execute(GenerateAction.java:37)
        at com.pmease.quickbuild.plugin.report.engine.generator.DefaultGenerator.generate(DefaultGenerator.java:36)
        at com.pmease.quickbuild.plugin.report.engine.contribution.publisher.AbstractPublisher.run(AbstractPublisher.java:129)
        at com.pmease.quickbuild.plugin.report.nunit.NUnitPublisher$$EnhancerByCGLIB$$5d780bf1.CGLIB$run$24(<generated>)
        at com.pmease.quickbuild.plugin.report.nunit.NUnitPublisher$$EnhancerByCGLIB$$5d780bf1$$FastClassByCGLIB$$be508917.invoke(<generated>)
        at net.sf.cglib.proxy.MethodProxy.invokeSuper(MethodProxy.java:167)
        at com.pmease.quickbuild.DefaultExpressionManager$Interpolator.intercept(DefaultExpressionManager.java:280)
        at com.pmease.quickbuild.plugin.report.nunit.NUnitPublisher$$EnhancerByCGLIB$$5d780bf1.run(<generated>)
        at com.pmease.quickbuild.stepsupport.Step.execute(Step.java:498)
        at com.pmease.quickbuild.stepsupport.StepJob.execute(StepJob.java:37)
        at com.pmease.quickbuild.grid.GridJob.run(GridJob.java:114)
        at java.lang.Thread.run(Thread.java:619)
    Caused by: com.pmease.quickbuild.plugin.report.engine.exception.TypeCastException: Can't convert object<NaN> from java.lang.String to DURATION
        at com.pmease.quickbuild.plugin.report.engine.datatype.DurationType.fromString(DurationType.java:140)
        at com.pmease.quickbuild.plugin.report.engine.generator.xpath.XPathRule.doExecute(XPathRule.java:98)
        at com.pmease.quickbuild.plugin.report.engine.generator.GenerateAction.execute(GenerateAction.java:37)
        at com.pmease.quickbuild.plugin.report.engine.generator.AbstractProcessor.executeRule(AbstractProcessor.java:119)
        ... 16 more
13:08:37,1 [publish-report-tests-nunit@lab9:8811] INFO - Workspace mutex released.