Backup Error

[msf004]

I recently added a dedicated HDD for backups, mounted this new HDD as /backups and then symbolically linked /opt/zimbra/backup to /backups.

After this change I am now getting nightly backup errors:

Message:  incomplete backup full-20110720.060108.434: 
/opt/zimbra/backup/sessions/full-20110720.060108.434/session.dat.tmp 
was not renamed to session.dat; backup did not complete successfully
Error code:  backup.INCOMPLETE_BACKUP
Method:  ZmCsfeCommand.prototype.invoke
Details:soap:Receiver

I checked the /backups directory, and the owner/group is both zimbra and the rwx is : rwxrwxr-x

Any thoughts on where I can look to see what is going wrong?

Thanks,
-Marc

(Version 4.5.11_GA_1752.RHEL4)