pyglet.resource.ResourceNotFoundException: Resource "data/queen.png" was not found on the path.  Ensure that the filename has the correct captialisation

Cosmo and Rectifier pointed out a bug:

pyglet.resource has a cache. This cache gets invalidated by the previous games you played (but didn't happen on my machine, as I played my game first).

Cosmo fixed it by adding (at the top of run_game.py) :

    pyglet.resource.path = ['data']
    pyglet.resource.reindex()

    and removing "data/" from all the resouce loads.

It might be possible to just do:

    pyglet.resource.path = ['.']
    pyglet.resource.reindex()