I have the wk-3000. In it's use of the SmartMedia card...I need to 'format' the card, using the Casio slot (not the computer). Once formatted, the Casio creates a folder on the Smartmedia card called 'MD_Casio'. All smf files must be placed in that folder to be able to be 'read' by the Casio. The smf files must also be in the 'midi 0' format. I hope this will help you.