The SD card should be freshly formatted before doing a flash from it, but I said to you before I use CF cards for installing ROMs.
You didn\'t tell me yesterday what desktop OS you run, so I will guess it\'s a Windows-type. You should copy off any valueable data from the card to your hard disk, then format the SD card, like you would format a floppy. Are you using an external card reader? Some card readers have their own formatters. It\'s best to format the card, I\'ve had some problems with unformatted cards, you won\'t want to run into additional problems doing something like this.
Once the card is blank, drag-n-drop the 3 files to it. This shouldn\'t be anymore difficult than copying to a floppy disk. They should be the only 3 files on the card.
Give it a try and let us know.