downloading games

i need some help as i am really new to this. i have a R4 and have saved some games from this site to download. when i transfered them to card and tried to play them all i got on ds screen was "could not read data" what am i doing wrong. if anyone replies can you keep it simple please, im not all up on this new stuff. thanx

Update your firmware at http://www.linfoxdomain.com/ds/.

You could also download it from http://r4ds.cn/download/r4.html