Hello Mike,
I'm the guy that is guilty for this tool
. I'm reading a lot in this forum but had no registration so far. Today I saw this thread and decided to register and to try to help with APT.
I had not chance to test the program with 10D myself, so can't guarantee that it will works correctly with your camera. Can you try to connect the USB and serial cable at same time? Then select from "Long Exp. Control" list the COM port that is connected to your serial cable (BTW take a look on the "Camera Preparation" steps in the User's guide). With all these steps it is expected APT to allow to command the camera like setting the ISO and to make exposures longer than 30s.
Regards,
Ivo