A bug me thinks
When creating a new extension ‘X’ with freepbx 2.2B2, a symlink ‘X’ is created in /var/spool/asterisk/voicemail/device/ pointing to /var/spool/asterisk/voicemail/device/X !!!
Hence, symlink pointing to itself!!! 
Just in case anyone else comes across this problem: somehow /var/spool/asterisk/voicemail/device was created as a symlink to /var/spool/asterisk/voicemail/default. Not sure if this was something I did, or if PBX in a Flash came like that. Reverting /var/spool/asterisk/voicemail/device to a directory (with appropriate ownership) fixed the problem.