The layout and image files have to be named correctly and in the appropriate directory in order to work.
Create a folder inside the LAYOUTS folder called "mylayout" or whatever you want. place your driving.lay file in that folder along with the background image file for your layout. Then rename the "driving.lay" to "Layout.lay" and rename the image file to "main.jpg". You may also want to load up the layout designer and load your layout and choose the background image again just in case.
In the Mamewah.cfg file changet the Layout to mylayout: ie.
;MISC OPTIONS
Layout Name = mylayout
Keep Image Aspect Ratio = True
Refresh Snapshot Every Time = False
Mouse Pointer = False
Task Switching = False
WINIPAC Filename =
Refer to "layouts.txt" for full instructions on creating your layouts.
If you are creating multiple emulator skins you'll need to name each ".lay" and background image file according to instructions in the "layouts.txt" file.