Can't Get Mortal Kombat 4 To Boot [SOLVED]

[Soup'um]

I've been setting up my arcade and everything's going great, but I can't get Mortal Kombat 4 to boot. I've gotten Tekken 3, SoulCalibur and Virtua Fighter working, so it's not a problem with 3D games in general.

I've gone looking for a Midway Zeus ROM, but I can't seem to find one, and everything seems to point to a driver inside the ROM emulating the hardware, not a separate ROM.
I'm using 0.159 versions of mk4.zip, mk4a.zip and mk4b.zip, with mk4.zip mounted, and the other two sitting in the roms folder. They work fine in the version of MAME 0.159 downloadable from the MAME website.
I've also tried a more recent ROM, which displayed a internal MAME window that seems to be for setting up lightgun games. A beep sounded a few seconds later, and then the game crashed.

Is there something I've missed, or is my ROM incompatible?

[Vermillion]

After digging a bit, it seems the 2014 MAME core doesn't like Mortal Kombat 4 for whatever reason, resulting in this mess:

https://steamcommunity.com/sharedfiles/filedetails/?id=1429088206

Instead, try using the MAME LightGun core that is linked in the Arcade Builder guide. It should work fine then.

https://steamcommunity.com/sharedfiles/filedetails/?id=1429089543

[Soup'um]

Tried the MAME LightGun core with my 0.159 ROMs and they still crashed, but the newer ROM booted fine. Weird, but I'm not complaining.

Thanks for the speedy help.