A lot of these problems are simply caused by the R4 Gold not making good contact with the connectors in the DS. This can corrupt the micro SD card so it cannot be read by anything and cause the DS to report system errors or not be recognised at all. I found the solution on this site earlier. A small thin piece of cardboard stuck on top of the R4 fixed the problem for me. I fixed the corrupted SD card by fromatting it in a mobile phone and then used the Panasonic SDFormatter to reformat the card to the correct size. Copied the kernal and the games back and everything works beautifully.