I haven't seen that error. When I was having problems, it was the unknown romset error.

I'm wondering if it's possible the roms are bad or not neogeo roms. Possibly neogeo pocket roms, which are different?

Just throwing out wild guesses here.

Why don't you try to find a rom for a game called joyjoy. It's small, so it's a good test, and I know it works. The version I have is:
joyjoy.zip 1000912

When looking, make sure you grab the MAME neogeo version of the rom, not the neorage version.

desiv