OK, some progress ... sort of.

Having given up on this particular problem, I went on to start another Qt project. Used designer to set up a QMainWindow with a QVBoxLayout as its central widget, built a release load and it seg faulted somewhere in my ui_file.h file on a call to my QVBoxLayout object. Tried a debug load and it worked (just opposite of what was happening above). So I dug through the makefile system that NetBeans generates and found that there are make options available at the command prompt that are not available via the IDE. From the project directory:

$ make clobber

This clears out everything but the source and .ui files (.o, core, executables, etc.). Then, also from project directory:

$ make CONF=Debug build
$ make CONF=Release build

This builds a debug version, and a release version. After this both version of my new program worked. I tried this on the afore mentioned project ... also worked. Apparently something is not getting updated properly with a simple build. Whether its NetBean's make system, or the compiler itself, I do not know (although based on my experience so far with this version of gcc, l'm leaning toward the compiler).

FYI:

$ make help

from the project directory will describe the command line options available through NetBean's makefile system.