Thanks everyone for your responses. I finally figured it out, it was where I was placing the files. I did download Calibre also, but for some reason I like Mobi2mobi better, but I do use Calibre when mobi doesn't work (which has only been on 3 books, so far).
I don't think anyone can answer this, but I feel the need to complain about it. We are stationed in Japan, so I download to the computer than transfer to the kindle. I have 2 kindles on the same amazon account and I have to download the same book twice to put it on each kindle. I don't understand this. Why can't I download it once and then be able to read it on either kindle without downloading it twice and having to have two seperate backups for the same book. I also have to change the metadata in both downloads. It seems if you were on the same account you should not have to do this twice or more. Considering getting a kindle for my husband but I do not want to do the downloads three different times for each book.