I have Install MAMECE3 For Pocket PC Version 9.40 in my Cassiopeia E-125 pocket PC and i have game ROM: 1942 (set 1) and Frogger. Unfortunally, I can not playing the games: "Insert Coin" appear in screen and I already pressed Action button (scroll button in right side) but no effect. Anybody have solutions? Help me please, thanks & regards.

You need to define the keys and set one of the keys to 'add coin'.

On the Asus i use when i press the recorder button (on the top of the unit) i've set it up to act as the 'coin' button

Give that a go. Like i say you need to make sure you have a button defined for the coins