For some reason, on my 64-bit system, PinPoint can't write out the simulated image. WriteFits fails even though thepath is fine and the folder exists. This may affect lots of other things!
The problem affects all pointing updates! The (x86) in the path triggers CFITSIO's goofball path features. Move PointingExps to MyDocs\ACP\Images\PointingExps and it works!