Dpkg and missing files list for packages

[Roberto Sebastiano <robs@multiplayer.it>]

Hi,
I've accidentally lost some data in /var/ directory (specifically
/var/cache /var/backups /var/lib/apt), and now when installing a new
package dpkg complains about missing files list for some packages.. it
outputs something like:

dpkg: serious warning: files list file for package `python' missing,
assuming package has no files currently installed.

and so on for many packages.
Is there any way of fixing this *without* reinstalling the machine from
scratch ?

Thanks
-- 
Roberto Sebastiano <robs@multiplayer.it>