Time Machine locked on "Looking for backup disk"


since a couple of days, my Time Machine backup do not work and stays on “Looking for backup disk” (at least the whole night without starting).

I still can open Time Machine and navigate in its history.

I’m running Lion 10.7.2 and I’m using a MBWE White Light with the latest firmware (.12).

I don’t know if it’s normal but some of the files in the /DataVolume/.timemachine folder have strange rights.

For instance:

/DataVolume/.timemachine # ls -al
drwxr-xr-x    8 WD_Backu root         4096 Nov  3 19:34 .
drwxr-xr-x    9 root     root          127 Nov  1 10:51 …
drwxr-xr-x    2 WD_Backu root           81 Oct 21 20:41 .AppleDB
drwxr-xr-x    2 WD_Backu jewab          21 Jul  3 12:12 .AppleDesktop
drwxr-xr-x    2 WD_Backu jewab          36 Nov  1 20:54 .AppleDouble
-rw-r–r--    1 WD_Backu jewab        6148 Nov  1 20:54 .DS_Store
drwxr-xr-x    3 WD_Backu jewab          25 Jul  3 12:12 Network Trash Folder
drwxr-xr-x    3 WD_Backu jewab          25 Jul  3 12:12 Temporary Items
drwx–S—    4 WD_Backu jewab        4096 Nov  3 19:34 iMac.sparsebundle

Do you know if it’s normal?

Is there a way to solve the “Looking for backup disk” problem?

Here is Time Machine log:

Starting standard backup
Attempting to mount network destination URL: afp://wd_backup@MyBookWorld.local/WD_Backup
Mounted network destination at mountpoint: /Volumes/WD_Backup using URL: afp://wd_backup@MyBookWorld.local/WD_Backup
Disk image /Volumes/WD_Backup/iMac.sparsebundle mounted at: /Volumes/Copies de sauvegarde Time machine
Backing up to: /Volumes/Copies de sauvegarde Time machine/Backups.backupdb


The rights on the files are normal. I have seen this before, one of my friends was having the same issue here, we look in the Apple forums, there are a lot of users reporting this issue, in the end, we just reset the NAS and Time Machine started to work.