ok, for one, you dont want an ISO file. you want a .map file. the ppf file should tell you which level you need to apply it to, usually blood gulch, sometimes sidewinder. it could be something else, too, but its bg or sw 99% of the time. anyways, in PPF-O-Matic, dont go under the "xbox" setting, just go to the normal setting, so you can select all file types. FTP to your xbox and transfer over an UNALTERED, ORIGINAL copy of the map. look for it in the maps folder of your halo directory, because you want the compressed version, not a cache file. apply the PPF to the map, and send it back over to your xbox and overwrite the map file already on your xbox. you should end up with a modded map in your map folder replacing the normal map. so go load up halo, and play the map you put in (it'll have the name of the original map, so dont go looking for the modded level's name). congrats, you should now be playing the modded map.