> But see, I get no errors with BioFreak on vanilla MAME. CMP validates it
> perfectly, no errors at all.

If you use a mame which has a not complete entry for biofreak harddisk (like all mame's < 78) and got no biofreak subfolder in one of your rompaths, you won't see the message. You won't see the message either if you have that subfolder and a correct chd entry for biofreak. You only see it if you got a datfile/mameexe with a bad entry and a subfolder.

Roman Scherzer
ClrMamePro