Asar doesn't have any RAM detection, it probably said ROM.
Anyway, the most likely cause of this is typoing the ROMs file name. Make sure you spell them exactly as they are including the extension (most likely .smc).
You can also drag and drop the files in the window when it asks you for them which can prevent these kind of errors.
In case it does say RAM, post the exact error it gives you, it might be a missing define or file as well.