Test log reports:
'6/23/2014 10:08:56 AM' - 'Fail' : 1. [parentTest_CodedStep] : New Coded Step
------------------------------------------------------------
Failure Information: 
~~~~~~~~~~~~~~~
Exception thrown executing coded step: '[parentTest_CodedStep] : New Coded Step'.
InnerException:
System.NullReferenceException: Object reference not set to an instance of an object.
   at ArtOfTest.WebAii.Design.BaseWebAiiTest.ExecuteTest(String relativeTestPath)
   at simpleSubtest.parentTest.parentTest_CodedStep() in f:\Dropbox\Support Issues\simpleSubtest\parentTest.tstest.cs:line 52

But this is impossible because the reference line of code is this:
this.ExecuteTest("childTest.tstest");

It's the child test that threw the assert:
                ArtOfTest.Common.UnitTesting.Assert.IsFalse(true, "THIS IS MY ASSERT MESSAGE");

Attached is a project that reproduces this problem.