Unable to exclude SecurityRisk.URLRedir from HOSTS file scan

I have a large hosts file for blocking ad sites and NAV 2010 keeps detecting a security risk and removing the last line of the file whenever it scans. To try to prevent this, I've added the hosts file, C:\WINDOWS\system32\drivers\etc\HOSTS, to Scan Exclusions and Auto Protect Exclusions and added SecurityRisk.URLRedir to Signature Exclusions. What else can I do to prevent NAV from scanning this file?

 

As a work around, I even tried duplicating that last line, which happens to be

127.0.0.1  jiangmin.com

 I was hoping it would only delete the last line as before, but unfortunately NAV removed both lines. At least, once it gets rid of each 127.0.0.1  jiangmin.com, it hasn't deleted anything else yet. It isn't a major problem that a line was deleted, but it's annoying that I can't stop it from happening.

 

[edit: changed subject to better reflect thread topic] 

Message Edited by Tim on 11-16-2009 06:39 PM