Erreur avec rdiff-backup

[Thibaud Hulin <hulin.thibaud@wanadoo.fr>]

Bonjour !
En lançant mon script de sauvegarde rdiff-backup, j'obtiens un message 
d'erreur :

SpecialFileError run/dbus/system_bus_socket Socket error: AF_UNIX path 
too long
SpecialFileError run/mysqld/mysqld.sock Socket error: AF_UNIX path too long
Fatal Error: Bad rdiff-backup-data dir on destination side

The rdiff-backup data directory
/media/hda5/backup/home/rdiff-backup-data
exists, but we cannot find a valid current_mirror marker.  You can
avoid this message by removing the rdiff-backup-data directory;
however any data in it will be lost.

Probably this error was caused because the first rdiff-backup session
into a new directory failed.  If this is the case it is safe to delete
the rdiff-backup-data directory because there is no important
information in it.

Je ne comprends pas ce qu'est cette histoire de valid current_mirror 
marker ?
Merci d'avance,
Thibaud.