Solution:

You'd better give up to use QBASIC to compile your program because ADAM-4500 just supports ROM-DOS which is only compatible with MS-DOS, not real MS-DOS. So there are many bios functions ADAM-4500 doesn't provide ( please refer to the manual to get advanced information about bios function ). If you download this kind of executable file into ADAM-4500, you will get an error message when you run it. Therefore, you are recommended to use TC3.0 or BorlandC 3.1 instead of QBASIC.