Finally got a chance to check out the AppGameKit demo. In the custom text example, it says
This line matches the ASCII code for the letter A, which is 65 to coordinates 76, 126 on the image and tells us that the letter A is 25 pixels wide and 42 pixels high.
But the code it shows is only: 76:126:25:42
And if I understand the rest of it ok, it should be
65:76:126:25:42