I had a really hard time geting the Dig Dug and Galaga roms to work in MAME and when I searched the Internet I couldn’t find anything. The response I saw over and over was that the roms must not match the MAME version I was using but I had tried several and still nothing Then I stumbled onto the answer and it’s pretty simple, I was missing some other ROMS. The ones I was missing were the following:
I just grabbed all the Namco ROMS and wasn’t sure which one was the problem but it works so I can’t complain. I found this problem with clrmamepro when I used it to verify my roms. I then went to retroroms and grabbed the Namco ROMS and the problem was solved. It is well worth it to learn to use clrmamepro even if it is really confusing. So there you go, if you get the error that you are missing ROMS or CHD then you probably need the namco5x.zip roms. Happy Dig Dugging!!!
Update: I was informed in the comments below that you only need Namco51 and Namco53. I haven’t tried just using those but it’s probably correct. If not then throw the rest in there.