The cause and fix is obvious but it means the examples are untested.
The following are lines 6, 7 and 8 from the Hello World example
#define BACKLIGHT_PIN 7 #define CONTRAST 110 LiquidCrystal lcd(12, 11, 5, 4, 3, 2, BACKLIGH_PIN, POSITIVE );
Notice the selling of "BACKLIGH_PIN" in the last line.
The issue here is that perhaps a regression test is not being run?