Sounds like to many conversions. Some convertors don't work with all devices. Try doing one convertor at a time. Like just plug in the joystick to the joystick port, does joymouse work? Plug in the joystick to the USB adapter does it show up as a device and does it work.
Your MAS joystick might not work but your Gravis pad might. Thats just the way convertors are, some work with some devices. If they were universal we wouldn't need convertors.