>Is there a way to test that a device is capable of writing data before trying to write to it and get a program error? I have clients who don't know or understand that you can't write to a distribution CD but they select it from the directory and then my program tries to write to it and then displays program errors.

Look at http://www.berezniker.com/display/VFP/Enumerate+Available+Drives though this is not exactly it, but may be a starting point.