Loadman, i tried again and it only works if I change the file mame.ini
I'm using the 1662 version of MALA and wolfmame 0.138.
What does the logs say? Particularity on the 'Starting Game' section
What have you got set in the 'Command Line' on the options- mame - basics tab.?
Are you using a 'command line' version of mame?
What happens if you don't specify 'anything' in mame,in?
Please provide answers to these questions in order for me to follow up. Thanks

My tests were using 1662 and mame .89..107 & .110 and worked with two different directories set in MaLa. I could not test on later versions of mame as I don't have the right roms for teh latest versions)
Later..... OK I did some tests.
It seems mame changed the way you need to specify rom paths at some point (somewhere between .110 and .125)
Try this command line.
-rp %path% %rom%This worked for me with version .138 and a free rom 'Start Fire' I got from the mame website.
So I think this issue is solved

For future issues I encourage all to look at the logs and see what mala is passing to mame on game start
MaLa is designed to be flexible and future proof by allowing you to alter the parameters passed to mame.
The only thing I had to do to get it working was read the config.txt on the latest mame version
-rompath / -rp <path>
Specifies a list of paths within which to find ROM or hard disk images.
Multiple paths can be specified by separating them with semicolons.
The default is 'roms' (that is, a directory "roms" in the same directory
as the MAME executable).
You can always do quick manual tests using a commend prompt (see attached screen shot)