Shouldn't vifm try to open with the next program when the first one is not installed?
It already does. I would say that the problem here is with OS X, i.e., the command is
open -a MPlayerX.app,
the application in this case is open
and that's all Vifm checks for existence. I'm not sure if it's possible to rewrite open -a something
in a normal way to fix the behaviour. If it were
MPlayerX.app,
then everything would work, but I'm not sure whether OS X allows this. So you need to put normal applications (by "normal" I mean not .app
-things) before open -a ...
.