[Dirvish] Explanation Needed of Error Message

[Rich Shepard]

   When I logged in this morning I saw messages on the console (prior to my
logging in) related to /dev/sdb1 but did not write them down. This device is
my dirvish backup drive (mounted as /media/hd0). /var/log/messages shows
only:

Aug  8 00:30:01 salmo kernel: kjournald starting.  Commit interval 5 seconds
Aug  8 00:30:01 salmo kernel: EXT3-fs (sdb1): using internal journal
Aug  8 00:30:01 salmo kernel: EXT3-fs (sdb1): mounted filesystem with
ordered data mode

   However, only two of six partitions were backed up; a message from root in
my inbox tells me:

>From root at appl-ecosys.com Thu Aug  9 00:37:35 2012
Date: Thu,  9 Aug 2012 00:37:35 -0700 (PDT)
From: root at appl-ecosys.com
To: root at appl-ecosys.com
Subject: cron for user root /root/dirvish-backup.sh

salmo-usr:default:20120808-2200: cannot open log file /media/hd0/salmo-usr/20120808-2200/log
cannot open config file: default.conf
cannot open config file: default.conf

   The drive is only about 38% full. I've not before encountered an error
like this so I would appreciate some insights from you more experienced
users. Was this just a one-off glitch or an indicator of a problem that is
not immediately obvious to me?

Advice needed,

Rich