title: cannot import rpy2.robjects but can import rpy2
body: <p>I developed a web tool by python, cgi, rpy2 and R, it works well on my personal computer. </p>
  
  <p>So I am tryig to set it up on the server. The versions of the software I used on the server are shown below. </p>
  
  <p>And I test rpy2 in command line, it works well. However, rpy2.robjects can not be imported when I run the web tool.  It returns the following error:</p>
  
  <pre><code>Error in .Call("R_isMethodsDispatchOn", onOff, P...aseenv.get("show")
  LookupError: 'show' not found
  </code></pre>
  
  <p>What's more surprising is that I can import rpy2.  Dose any one has similar experience?</p>
  
  <pre><code>System: CentOS release 5.7
  Python version: 2.7.8, 
  R version 3.1.1 (2014-07-10), 
  rpy2 version: 2.4.3
  </code></pre>
  
  <p>Thanks</p>