I did upgrade to Mame 164, but 164 claims that the ROM works. Any ideas?
Sometimes roms are renamed, reorganized or changed along with MAME.
Sometimes sound board or bios roms are taken out of the main rom and given their own separate rom if they were used in multiple games.
The new version of MAME is probably looking for something in a different place than it was located in previous versions.
What version of MAME did you update from?
The change would be mentioned in the "What's new?" file from between the old version and new.
You probably need to update your roms or download new ones.
Roms have different revisions, just like MAME does.
There usually aren't any massive changes, so the bulk of roms from older sets will work with new versions of MAME.
But individual games will stop working here and there.