Monster Rancher DS

So a while back now my computer broke and with it went all my back up files for my r4 that I needed since my r4 memory got "erased". How? I don't know, so now I am trying to get the games I had and start over but Monster Rancher DS a game I loved to play isn't able to transfer into my r4. I am able to download it but whenever I try to import it into my r4 winwar say the operation could not be completed due to the file being corrupt. It is a very saddening fact since I had the game before. If possible can someone please give me an explanation or a solution to my problem.Thank you

Re: Monster Ranceher DSthe file you have has corruptedso redownload the game and format your sd so no problems happen again

Re: Monster Ranceher DSIve redownloaded it more than a couple times now, what do you mean by format my SD?