title: Unable to knit R program (there is no package called 'backports'
body: <p>I am new to R. Its says there is no package called backports. I tried installing package called backports and loading it but it's not getting installed. And I am not able to see  mark down in HTML format. I am using Rstudio. </p>
  
  <p>This is what I am getting as an error everytime I click on Knit:</p>
  
  <blockquote>
    <p>Error in loadNamespace(i, c(lib.loc, .libPaths()), versionCheck = vI[[i]]) :        there is no package called 'backports'<br>
    Calls: :: ... tryCatch -> tryCatchList -> tryCatchOne ->  Execution halted**</p>
  </blockquote>
  
  <p>If I do <code>install.package("backports")</code>, I am getting this </p>
  
  <blockquote>
    <p>Warning in install.packages :   installation of package ‘backports’ had non-zero exit status**</p>
  </blockquote>
  
  <p>Thanks in advance.</p>