"Here's my work-around solution to arduimu.cpp's clobbering of Arduino's analog_reference.
In the header section of arduimu.pde add this line: #include <pins_arduino.h>>


In the setup() procedure, add one or both of these two lines:

pinMode(…"

"Partially answering my own question...

The problem is that adruimu.cpp defines its own analog_reference rather than importing it from Arduino's wiring_analog.c. (Probably because somebody took a shortcut, which is now biting me.) For everybody else…"

"Thanks very much for your reply, Chris. I was following the usual Arduino startup routine. Just assumed that Blink would work, trying to take very small steps. I guess too small in this case. Thanks to your guidance ArduIMUTest.exe is now working.…"