The RevoScaleR package did not include a vignette file, only .pdf documents. The index.html file is missing. You can create a new index.html in the folder /library/RevoScaleR/doc and add the following contents using gedit or other text editor.
------------
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html><head><title>R: Vignettes</title>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<link rel="stylesheet" type="text/css" href="/doc/html/R.css">
</head><body>
<h1> Vignettes
<img class="toplogo" src="/doc/html/logo.jpg" alt="[R logo]">
</h1>
<hr>
<div align="center">
<a href="/doc/html/index.html"><img src="/doc/html/up.jpg" alt="[Top]" width="30" height="30" border="0"></a>
</div>
<h2>Vignettes from package 'RevoScaleR'</h2>
Sorry, the package contains no vignette meta-information nor an index.
Please browse the <a href=".">directory</a>.
</body></html>
-------------
Then simply save the .html file. You should now be presented with a link to the directory and can select any of the ScaleR documents in .pdf form.