I have an MZ-RH10 and a couple of dozen HIMD-discs, and some of them (not all though) have occasional problems when uploading HI-SP or PCM-recordings from the disc to SonicStage; when this happens, "Access Error" is displayed on my MZ-RH10's screen and the track fails to upload further. If I retry uploading the 'problem track', it succesfully uploads (sometimes with certain discs this has required more than one retries, but in the end I have never been not able to upload tracks because of this error). I checked the forums a bit and some other people apparently have had this problem too. Anyway, it appears that 4.3 handles this situation a bit slicker than 4.2 and the earlier versions.