Are you on Rasbian Wheezy? If so, you shouldn't be using Chromium. Using Chromium on Raspbian Wheezy is now a security problem, as new versions of Chromium won't build on Wheezy. If you want to keep using Chromium, upgrade to Jessie, but beware of the dangers of Debian Testing. If you want to use Chromium but still want the reliability of Wheezy, you will be at security risk and will no longer get any Chromium updates.