i got a different version, called mameuifx32_0122u6 its awsome and easy to use but it doesnt recognise my dual action control pad...
....i just cant seem to make it work argh!
First make sure you have 'enable joystick' selected in the control config tab from the main toolbar at the top.
Next go to the mameuifx folder, and look for the 'cfg' folder and delete the file in there called default.cfg (mame will automatically generate a new one when you run it).
Now open a game, hit TAB, then select 'input general' and remap your controls in there, this will remap the controls for all games. Select the control you want to remap, hit 'Return' then push the joystick direction/button you want to map it to. Repeat until all directions and buttons are mapped.
If you've done all that and it still doesn't work then your joypad may not be supported.
Mameuifx is an unofficial enhanced build of MameUI (its not called mame32 anymore).
Hope that helps.