What happens if you
0) disable the fatfingers plugin
1) load in the 45 degree map yourself
2) launch mala->launch qbert
Then also try not doing #1. (obviously the qbert controls will be weird, but at least it'll respond)
We need to find out if it's the map, qbert itself, a MAME config gone wonky, or the plugin loading the wrong file-there are too many variables at this time.
I have this exact same setup on my cocktail machine, and the plugin works perfectly for both player 1 and player 2, although I am using RC8 MaLa.