Comment 4 for bug 832960

This looks like there is an error with magic data and how memcached is configured. This is potentially an error that we have seen with Ubuntu. Can you please tell us the version of all the software.

For ubuntu:
  lsb_release -a

For PHP:
  php -v

For memcached
  aptitude search memcache
  aptitude versions memcached php5-memcached

The instructions for installing memcached are here:
 http://open.intrahealth.org/mediawiki/HowTo:_Install_Memcached
Can you verify which instructions you followed.