title: Using as.POSIXct in R giving na for identical character structures
body: <p>I have two timestamps in character form that I want to convert to a POSIX format in R.
  The <code>timestamps</code> are:</p>
  
  <pre><code>1: "2013-03-30 17:45:00"
  
  2: "2013-03-31 02:05:00"
  </code></pre>
  
  <p>The first one converts fine, the second one gives me <code>NA</code>. The <code>timestamps</code> are downloaded as <code>characters</code> from an <code>SQL server</code>. Anyone have any ideas what is going wrong?</p>
  
  <p>I don't have the reputation to attach a screenshot, so a screenshot of my R console showing the result is provided here: <a href="http://emillarsen.com/r%20console.jpg" rel="noreferrer">http://emillarsen.com/r%20console.jpg</a></p>