having same issue with version 0.159 rom set. I think ot has something to do with a change from game to machine in the xml structure. But I am unable to use as well. Does simple arcade multiplier allow you to import into launch box or are you using that as your front end? Also, can I just manually somehow add the roms that I want to use?
I have everything up and running for all of my emulators, etc. However, when I attempt to import mame rom set, the following error shows up and I am unable to proceed past this point. Mame.xml child node not named "machine" and fails import Is there a work around for this or a way to correct? Is it that my ROM set is so old that is causing the issue?