Recently a number of reuploads were done in response to complaints that the mediafire links didn't work. It was confirmed at that time that there was a message "server not found for this file. Try again later." for those links.
I went back to the links again yesterday and today and found that all those old affected mediafire links worked again. Maybe if it happens again we should wait one week before reuploading. Such problems could be due to the mediafire site having system problems which would be resolved eventually.