title: Can't start Python - ImportError: No module named posixpath
body: <p>So I have an application written in Python that uses virtualenv with Python 2.7.3. Application runs some tasks with rabbitmq and celery. Everything was running smooth for couple days and today I noticed tasks are not being processed. I logged in to the server and noticed that rabbitmq is down. I started up rabbitmq server and then tried to start python interpreter and I get:</p>
  
  <pre><code>Traceback (most recent call last):
    File "/home/marcin/pyProjects/resbit/venv/lib/python2.7/site.py", line 67, in &lt;module&gt;
      import os
    File "/home/marcin/pyProjects/resbit/venv/lib/python2.7/os.py", line 49, in &lt;module&gt;
      import posixpath as path
  ImportError: No module named posixpath
  </code></pre>
  
  <p>This only happens within virtualenv. I can start global Python without problem. My server (using Linode) wasn't restarted recently and as far as I know nothing was installed/updated. <strong>What could have happened?</strong></p>