Well...I feel absolutely stupid. Here's why:
I have been using some library functions I wrote 2 years ago. Buried a few levels deep, I was using these functions to help build the path I wanted:
System.Web.HttpContext.Current.Request.ApplicationPath System.Web.HttpContext.Current.Server.MapPath
Instead of using this:
HttpRuntime.AppDomainAppPath
System.Web.HttpContext.Current will be certainly null because there is no http context. And, of course, no exceptions were being thrown because I was trapping and ignoring them.
You don't know how many hours I was staring at my project wondering what the heck was wrong!
Please forgive me for wasting everyine's time. This is so embarassing!!!