title: R not finding package even after package installation
body: <p>I have always worked with the <code>zoo</code> package, that I have installed a long time ago. Today, I created a new R script, and ran <code>library(zoo)</code> and got the following error:</p>
  
  <pre><code> &gt; library(zoo)
   Error in library(zoo) : there is no package called ‘zoo’
  </code></pre>
  
  <p>Odd.. Still, I tried reinstalling the package using <code>install.packages("zoo")</code>, and get the following:</p>
  
  <pre><code> &gt; install.packages("zoo")
   Installing package(s) into ‘C:/Users/U122337.BOSTONADVISORS/Documents/R/win-library/2.15’
   (as ‘lib’ is unspecified)
   --- Please select a CRAN mirror for use in this session ---
   trying URL 'http://cran.cnr.Berkeley.edu/bin/windows/contrib/2.15/zoo_1.7-10.zip'
   Content type 'application/zip' length 874474 bytes (853 Kb)
   opened URL
   downloaded 853 Kb
  
   package ‘zoo’ successfully unpacked and MD5 sums checked
   Warning: cannot remove prior installation of package ‘zoo’
  
  The downloaded binary packages are in
      C:\Users\U122337.BOSTONADVISORS\AppData\Local\Temp\Rtmp404t8Y\downloaded_packages
  </code></pre>
  
  <p>When I try uploading the package, I get the error again that the <code>zoo</code> package doesn't exist.</p>
  
  <p>I have no idea what's happening. I exited the GUI and restarted it, same problem. I have always worked with this package, and I have no idea why this is happening now.</p>