You either need to reformat your memory card and reload the songs there again or you have to master reset the phone itself. The latter i can guarantee you that it's gonna work but you will lose contacts stored in your phone and pictures. However contacts stored in your SIM card will not be erased.I suggest you transfer your files first to a computer or another handset before master reseting your phone. You can find the master reset option in Settings last entry under General Options. Hope it works. =)
