it may be due to the anti-virus ur using.try disabling it.
Mmmmh ... maybe try this: First: sudo apt-get clean sudo apt-get autoclean apt-get autoremove etc ... Then if it's still not working, maybe this: sudo dpkg-reconfigure -phigh -a or sudo dpkg --force-all --configure -a or maybe: sudo dpkg -P --force-all 'package with a problem' (corresponding to: se-toolkit w3af subterfuge )...