I'm trying to restore trustees with metamig but I get the following error messages for every trustee present in the metamig backup file:

Error adding trustee .user.contextou.o to /media/nss/VOL/Dir: Bad user name(zERR_UNKNOWN_ERROR)

I used "metamig save VOLUME1 -n >/media/nss/VOLUME1/backup.trustees.xml" to backup and "metamig restore VOL </media/nss/VOLUME1/backup.trustees.xml" to restore.