Ok first you need to explain what you've tried so far and detail how you did everything along with what version OS your PSP has. Anyway's your a 1.50 OS ? And what version of Mame are you using? Your roms are zipped I assume. and you properly rezipped them ie: they are not a folder containing the roms that is zipped but all the files zipped into one zip file? Example pic of how to properly zip a rom included.
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