It's often come up that people have difficulty determing which romsets/files are required for MAMECE. Well, the following explains how to make that determination. It is described for MAMECE-10x, so it also applies to Ben's original MAMECE port and toe MameBoy. It should be similar in MAMECE3, I don't know, I haven't looked through the source.
-download the source
-scroll down to the stuff just after "#ifdef SMALL_COMPILE"
-find the driver name associated with the game giving you problems (for example "&pbaction_driver" for Pinball Action)
-look in the /src/drivers/ directory for a file by that name (i.e. "pbaction.c") (if there isn't one, it's included in another driver, you'll have to do a FIND, "Containing Text" to determine which file it's in)
-open the driver file you found in the above step
-scroll down (or use find) to locate the rom section of the driver, i.e. "ROM_START( pbaction_rom )"
-between the ROM_START and the following ROM_END it will list information about all the rom files needed by that game
-for example: "ROM_LOAD( "b-p7.bin", 0x0000, 0x4000, 0x8d6dcaae )" means filename="b-p7.bin", size of 0x4000 bytes (16KB) and the checksum is 8d6dcaae.
-the filename doesn't have to match for it to work, just the checksum
-you can compare to the checksums of the roms in your romset by using WinZip (Options | Configuration | View, make sure "CRC" is checked) than Winzip will show the CRC of each file in the zip