 <p>I stumbled upon this problem after upgrading php to 5.5 and reinstalling apache.</p> <p>Finally,this fixed it, in case someone else needs it.</p> <p><code>apt-get install libapache2-mod-php5</code></p> <p>(<a href="http://serverfault.com/a/243979/239598">here's the answer</a>)</p>