file-roller shows an error attempting to install the "unrar" command

[Andrea]

I have not yet installed the unrar package, so if I try to open a rar archive file-roller asks me to find a command to do it. When i click to "Search for a command" it gives me the error described in the attachment. This bug is reproducible.

ProblemType: Bug
DistroRelease: Ubuntu 12.10
Package: file-roller 3.6.0-0ubuntu3
ProcVersionSignature: Ubuntu 3.5.0-17.28-generic 3.5.5
Uname: Linux 3.5.0-17-generic x86_64
ApportVersion: 2.6.1-0ubuntu6
Architecture: amd64
Date: Sun Oct 28 14:30:19 2012
InstallationDate: Installed on 2012-06-11 (138 days ago)
InstallationMedia: Ubuntu 12.04 LTS "Precise Pangolin" - Release amd64 (20120425)
MarkForUpload: True
SourcePackage: file-roller
UpgradeStatus: Upgraded to quantal on 2012-10-19 (8 days ago)