Getting the same problem with SCCM 2012 on windows 2008r2.
Could not connect to registry hive HKEY_LOCAL_MACHINE\Software\Microsoft\SMS on computer Server. The operating system reported error 19: The media is write protected.
Not sure why this is happening because remote registry is switched on (dangerous), I can connect to it from a remote computer and change and edit keys. Looking for answer on this myself. Did you manage to resolve Kaaskyke
Best
J