missing _ds_menu.dat (???) on R4 for NDS

hi,i was having fun playing my games with my new R4 card for the last few days since getting it.a few hours after playing the DS, i turned it on and the top screen reads "couldn't find _DS_MENU.DAT"it was playing perfectly with games on it and everything... so, what have i done/what's happened?? and more importantly, how do i fix this problem which i hope others have had and have overcome..ANY help PLEASE ????????

Try reinstalling your firmware.http://www.linfoxdomain.com/nintendo/ds/Get it from that page and just drag and drop it into the root of your DS card.