> You need to turn on NES header support in Settings->Headers. And you should
> prefer datfiles in xml or clrmamepro format which already got the needed nes
> header reference in its datfileheader
>
>
> Roman Scherzer
>
Turned on the NES header with the same result. the dat file begins as this:

clrmamepro (
name "Nintendo Famicom & Entertainment System - Games - [NES]"
description "Nintendo Famicom & Entertainment System - Games - [NES] (TOSEC-v2007-02-14)"
category "Nintendo Famicom & Entertainment System - Games - [NES]"
version 2007-02-14
author etabeta
)

game (
name "!Mario (2000-11-19)(Dokokalaki)(Jp)[h][Super Mario Bros.]"
description "!Mario (2000-11-19)(Dokokalaki)(Jp)[h][Super Mario Bros.]"
rom ( name "!Mario (2000-11-19)(Dokokalaki)(Jp)[h][Super Mario Bros.].nes" size 40976 crc 2e2bf112 md5 b1a0e41cfd30c1d61de3b7900232de59 )
)

maybe it is for some older version of clrmamepro. but I can't find a new xml format dat file for NES.