SQL error on backup

[CarolV]

On my nightly backup, I've gotten the following error on the past 2 nights:
SQL error " DELETE FROM FileVersions WHERE BackupID IN (1) ; " - disk I/O error, disk I/O error (SQL81)
I am backing up to an external hard drive and can browse around it no problem.
Why is this happening and what can I do to fix it?
Thanks.

[Adrian (Softland)]

Hi,
What version of FBackup do you use?

Do you disconnect the device using Safely Remove Hardware?