ended up using this in my .ini for atari
### Execution Settings ###
emulator_executable E:\MetaCab\emulators\Atari2600\Z26\Z26.EXE
commandline_format [rompath]\[name].[romext]
alt_commandline_format_1 [name]{autodosbox}{nosafelaunch}
alt_commandline_format_2 [name]{autodosbox}{nosafelaunch}
game_specific_config_path
this fixed it!
So I did the same thing in the mame .ini
### Execution Settings ###
emulator_executable E:\MetaCab\emulators\Mame\mame.exe
commandline_format [rompath]\[name].[romext]
alt_commandline_format_1 [name]{autodosbox}{nosafelaunch}
alt_commandline_format_2 [name]{autodosbox}{nosafelaunch}
game_specific_config_path
no luck - was still having launch attempts return me to Mamewah.
So then it occured to me to try cleaning my mame install back to factory defaults (including the ditching of mame.ini in the Mame folder (not to be confused with the .ini Mamewah uses for Mame)). This worked! I had been using the mame.ini from
http://www.arcadecab.com/Projects/Mamewah-overview.htm and for whatever reason it was botching the system. Kill that and voila! Mame & Atari are working! yay!
thanks for the help everyone (especially to the voices in my head ;-P)