What version of Mamewah? In the latest version, the layout folder is defunct, and a basic layout is included:
http://mamewah.mameworld.net/downloads.htmThat should run almost out of the box, except for Mame v0.61, you should edit \mamewah\config\mame\mame.ini and set:
list_generation_method rom_folder_vs_listinfo
(by default this is _listxml to suit newer Mame versions).
Also check paths etc. in this ini file, and then run Mamewah, hit '2', select 'Games List Options' by hitting '1', and then select 'Generate List'.
HTH