Bug#740729: rkhunder cron.daily emit errors: Error: Invalid display - keyword cannot be found: Display line: display --to LOG --type INFO NETWORK_PORTS_DISABLE_PATHS

[gaio@sv.lnf.it (Marco Gaiarin)]

Package: rkhunter
Version: 1.4.0-1

By some days, rkhunter daily cron script emit a mail like:

 Date: Tue, 04 Mar 2014 14:04:54 +0100
 From: root <root at localdomain>
 To: root at localdomain
 Subject: [rkhunter] eraldo.localdomain - Daily report

 Error: Invalid display - keyword cannot be found: Display line: display --to LOG --type INFO NETWORK_PORTS_DISABLE_PATHS
 Error: Invalid display - keyword cannot be found: Display line: display --to LOG --type INFO NETWORK_PORTS_DISABLE_PATHS

looking around with google, seems that there's a ''incompatibilities''
between the db (updated by cron scripts) and the language file (AFAIK,
provided by package).

I'm seeking some feedback... thanks.