I have been getting the same error each time I try to install Canola2
"Unable to install. Software comtains updates to packages from a different source and is likely to harm the system. Contact the author."

This happens even after restart.
I also removed downloadmanager0-server and libdownloadmanager0 as per a previous thread suggestion. still no luck. I get the same error message.
below is the log from application manager

hildon-application-manager 2.0.1
apt-worker: domain change: python2.5-efl-utils (nokia-system -> unsigned)
apt-worker: domain change: lightmediascanner0-playlists (nokia-system -> unsigned)
apt-worker: domain change: hildon-imf-ecore (nokia-system -> unsigned)
apt-worker: domain change: lightmediascanner0-video-dummy (nokia-system -> unsigned)
apt-worker: domain change: atabake (nokia-system -> unsigned)
apt-worker: domain change: python2.5-efl-core (nokia-system -> unsigned)
apt-worker: domain change: lightmediascanner0-jpeg (nokia-system -> unsigned)
apt-worker: domain change: python2.5-terra (nokia-system -> unsigned)
apt-worker: domain change: liblightmediascanner0 (nokia-system -> unsigned)
apt-worker: domain change: canolad (nokia-system -> unsigned)
apt-worker: domain change: lightmediascanner0-plugins (nokia-system -> unsigned)
apt-worker: domain change: lightmediascanner0-id3lib (nokia-system -> unsigned)
apt-worker: domain change: efl-core (nokia-system -> unsigned)
apt-worker: domain change: libedje0 (nokia-system -> unsigned)

seems to be some python issue...