I think they need to be rerecorded, honestly, but I'm not sure what it is about the frequencies of these particular files that are tripping everything up. I suppose make sure you're recording in an insulated environment, make sure your mic is set up correctly, maybe try to match the enunciation of your other files... But at this point it's all guessing? I hope someone else can weigh in if they know more, but I can't seem to get these files to co-operate.