How I can modificate the Dremacast version to inclide other characters? I know that putting the char on CHAR dir and modificate de select.def file to include it, but When I generate a new cdi with this modifications, the main screen appears but when I press start to play it, the game crashes
Yeah, that should be the way to go. Did you try it with the Windows version? Maybe the Dreamcast version ran out of memory. Other than that, unlike the original Mugen, the Dreamcast version is picky with upper/lower case filenames. So if the original character creator didn't pay attention to that in the .def file, the character might crash.
If it also crashes in the Windows version, that's some error in the interpreter. On that note, I'm sorry about the lack of error output (e.g. infos about what went wrong, etc.), I'll add that in the next version. If you don't mind, could you tell me which character crashed so I can take a look too?