Install rootsh
Open an xterm
Type: root<return>
Type: apt-get install python2.5-hildon<return>
Do same as line above for the other packages
Type: exit<return>
Close xterm
Then try and reinstall your original target

You might have python2.5 installed, but you probably don't have python2.5-hildon installed, and I'm guessing Canola doesn't use it.

EDIT:

If in doubt, open an xterm and type:

dpkg -l | grep -i python<return>

and see what it says.