cuidado con los repositorios de distinta distro!

dpkg: error processing exim4-daemon-light (--configure):
 subprocess post-installation script returned error exit status 1
dpkg: dependency problems prevent configuration of at:
 at depends on mail-transport-agent; however:
  Package mail-transport-agent is not installed.
  Package exim4-daemon-light which provides mail-transport-agent is not configured yet.
dpkg: error processing at (--configure):
 dependency problems - leaving unconfigured
dpkg: dependency problems prevent configuration of exim4:
 exim4 depends on exim4-daemon-light | exim4-daemon-heavy | exim4-daemon-custom; however:
  Package exim4-daemon-light is not configured yet.
  Package exim4-daemon-heavy is not installed.
  Package exim4-daemon-custom is not installed.
dpkg: error processing exim4 (--configure):
 dependency problems - leaving unconfigured
Errors were encountered while processing:
 exim4-daemon-light
 at
 exim4
E: Sub-process /usr/bin/dpkg returned an error code (1)

Tenia este problema y googleando por ahi lei que tenia que ver con tener repositorios variados y hacer upgrade sin dist-upgrade. Tenia problemas de latencia irritante en la red y varias otras cosas con problemas.

1. Reinstale gnome
2. apt-get dist-upgrade
3. apt-get upgrade
4. apt-get autoremove (todos los paquetes que generaban problemas)
5. apt-get upgrade: ya no habia ningun paquete en espera, ni desconfigurado, y mi velocidad de navegacion se restituyo.