I cannot get some CD's that I have burned to mount on the stock drive in my 7500. The internal 7500 drive is a apple drive (4x I believe) and the CD's in question are CD-RW's two burned with toast files and folders and one with DirectCD on a Yamaha external 8x4x24. The discs all mount fine in my powerbook and my son's G3 CD-ROM drives, but no go in the 7500. any advice? also, the appropriate extensions are all there, so far as i know. thanks.