I'm also a user of Sony Minidisc Recorders (MZ/N10 and MZ/RH1) and had the same problems as you.
On internet I found the following solution:
1) Browse to the directory C:\Program files\Common files\Sony Shared\OpenMG\restorable, then you will find two files, namely icv.dat and maclist.dat;
2) Select both these files and copy them to the parent folder C:\Program files\Common files\Sony Shared\OpenMG;
3) After closing these directories etc. launch the SonicStage icon on your screen;
4) I have executed these procedure for both Windows XP (desktop computer) and Windows 7 Ultimate (notebook) and in both cases it was succesfull.