I have some problem with check sum, too. The test shows me KetA02 check sum error. Than I have done the reparature procedure as AJ wrote. Check sum was OK, but - the Styles instaled from Pen Drive was corrupted (with the blue point). Than I have reinstalled my Pen Drive - OK, Styles and Sounds seemed to be all right, but the check sum KetA02 shows error. AJ, can you help me, please? Sorry for my bad English.