Again, forum is elsewhere, but that command normally works fine in batch. If you are using the 0.2.0m1 release, I think run for project was broken, so it also may depend on your version.
I assume the script is a bit longer than that, or that you have run something else first? If you have run something else, there shoudn't be any need to set image type. And if you haven't run anything else, there may simply be no detections to export!