I have tried all of the suggestions listed above and nothing fixes the problem. When I use the settings on John's page I get a file can not be found error probably due to the rom names in quotes setting. I tried the changing the alt launch method and made sure the dos box setting was no. On some games I still get that dialog box and when i click on ok it just goes back to mamewah instead of launching the game. Some games do work, so I am really confused on what is causing this
Thanks