Windows Backup Problem


I have a problem with running my schedule Windows Backup when Comodo Internet Security is running. When I turns it off, the Windows backup run smoothly without error. I have checked my Comodo event log, and found this:

2014-05-17 21:00:47 \Device\HarddiskVolumeShadowCopy5\ProgramData\Comodo\Cis\Quarantine\data{3CA6077A-6A7F-47CA-8B2F-630D43AF9EEA} Application.Win32.InstalleRex.KG@309134933 Detect Success

I have seen in other post that this is a similar problem, as illustrated in;msg463950#msg463950. However, I am stuck at the step when one of post states:

[b]EricJH[/b] says: The AV log shows that a copy of the CIS quarantine is getting scanned. Try adding the following to the AV exclusions: \Device\HarddiskVolumeShadowCopy*\Program Files\COMODO\COMODO Internet Security\Quarantine\ . If it is formated properly I think it should stop the problem.

But I do not understand how to add the entry into the AV exclusion?

How do I know that is it not a true malware or so, or it is a false positive? My virus scan show that my terminal is clean.