Rudimentair, maybe you should try and reinstall the software, repair permissions and reboot? What version of "Hi-MD Music Transfer" are you using? You could also try and reformat the (Hi)MD. Please let me know what your experiences are.
Rudimentair, are you using MD or Hi-MD in your mz-rh1 ? Because transfering sound/music from 'old' MD's to the Mac using 'HiMD Music Transfer" is -not- possible.