I'm not sure if the most recent bug report with this issue was yours, but in the likely event that it is, it contained a useful stack trace:
System.Exception: Unknown DataRow parameter type: System.RuntimeType
at nCrunch.Module.MSTest.Integration.MSTestResolvedTest.convertStringToType(String stringValue, String typeName, Type parameterType)
at nCrunch.Module.MSTest.Integration.MSTestResolvedTest.DecodeAndResolve(ReflectedAssembly assemblyContainingTest, String encodedTest)
at nCrunch.Module.MSTest.Integration.MSTestTest..ctor(MSTestNames names, ReflectedAssembly assembly, ReflectedType fixtureType, PendingTest pendingTest, MSTestInterceptingContext testContext, Boolean considerInconclusiveTestsAsPassing)
at nCrunch.Module.MSTest.Integration.MSTestFixture.<>c__DisplayClass2_0.<.ctor>b__0(PendingTest t)
at System.Linq.Enumerable.WhereSelectArrayIterator`2.MoveNext()
at System.Collections.Generic.List`1..ctor(IEnumerable`1 collection)
at nCrunch.Module.MSTest.Integration.MSTestFixture..ctor(MSTestNames names, ReflectedAssembly assembly, TestName fixtureTest, IList`1 tests, MSTestInterceptingContext testContext, Boolean considerInconclusiveTestsAsPassing)
at nCrunch.Module.MSTest.Integration.MSTestRunner.runTestsWithinAssembly(IList`1 testsToRun, TestTaskOutput testOutput)
at nCrunch.Common.PerformanceTracking.PerfTracker.TrackUnreliableActivity(String name, Action activity)
at nCrunch.Common.PerformanceTracking.PerfTracker.TryTrackUnreliableActivity(String name, Action activity)
at nCrunch.Module.MSTest.Integration.MSTestRunner.RunTests(IList`1 testsToRun, TestTaskOutput testOutput)
at nCrunch.TestExecution.TestExecutionMonitor.PerformMonitoredTestExecution(Action testExecutionAction)
at nCrunch.TestExecution.TestRunnerThread.()
This is a hole in NCrunch's MSTest DataRow support. Somewhere in your test project you're making use of a DataRow with an unusual parameter type that NCrunch can't seem to handle. If you can get me the signature for the test that's causing it (unfortunately the log doesn't tell me which one), I should be able to investigate further.