Have you placed your source image in the data subdirectory? Yes. The image is in the data directory and data is at the same level as applet.

Is size the first call in setup()? Yes.

Other sketches are working. (Bad sign for my code.)
I'm using no external libs (Bad sign for my code.)

I had been using globals to assign values to size(). Unnecessary but ... I did it. Like this:

int MaxWid = 1000;
int MaxHt = 500;

void setup() {
      size( MaxWid, MaxHt );

I just changed the setup code to look like this:

void setup() {
      size( 1000, 500 );
      MaxWid = width;
      MaxHt = height;

Now the export method still fails but the box it's trying to put the executable in is the right size. Sometimes its white, sometimes black and then it stops running.