title: PHP intermittently unable to load json.so (PHP 5.4.19 on Ubuntu 12.04 LTS)
body: <p>I'm using Ubuntu 12.04 LTS and needed PHP 5.4 so I'm using <strong><a href="https://launchpad.net/~ondrej/+archive/php5" rel="nofollow">Ondřej Surý's</a></strong> (php5-oldstable) package. </p>
  
  <p>Both phpinfo and the CLI show that JSON is enabled:</p>
  
  <pre><code>#php -i | grep -i json
  json
  json support =&gt; enabled
  json version =&gt; 1.2.1
  </code></pre>
  
  <p>My application mostly works. But periodically (approx one page refresh in ten) there is a PHP error. This only happens intermittently.</p>
  
  <pre><code> PHP Startup: Unable to load dynamic library '/usr/lib/php5/20100525+lfs/json.so'
   - /usr/lib/php5/20100525+lfs/json.so: cannot open shared object file: 
   No such file or directory "json.so"
  </code></pre>
  
  <p>How do I fix this?</p>