Does it use the serial port for power or does it have external power? Some programmers snag a tiny bit of power to run from the unused status lines which may not work on some com ports? If you supply the programmer circuit power from an adapter it may work. This is a fault of the programmer not the serial port even if it works on other machines. The other machines may have full RS232 ports where as your machine does not. Are you using a serial to USB adapter on your computer? More specifics are required to help you.