If Disk Utility cannot repair the volume there is definitely something wrong with it. I would forget about MacDrive, if Mac cant access it MacDrive wont too.
If she can read from the drive while in OS X and there are no corrupted files I would just make an image with Carbon Copy Cloner before something worse happens and then, and only then, try to fix it. Cant help you with that though, I'm not sure how to do that if Disk Utility says it cant fix it, maybe some third party software like Disk Warrior can do it but I think none of them are free...