>>Found the problem.
>>
>>It appears that if the delegate method throws an error, the Code 99
>>error is reported. Luckily, I was able to trace the code and discover
>>the source of the error.
>
>Was it on the call stack? If not, how'd you trace it?

I traced to the call of the ReturnData method. Noting that the call was being redirected to my method, I started commenting out code. Soon it appeared as a syntax error inside the delegate method. Once corrected, the error went away.

FYI: I can now run a test suite that took 90 seconds in less the 15 seconds. too cool.