Finding and Replacing values in an XML
<p><a href="http://i.stack.imgur.com/fqqyE.png" rel="nofollow">Error and code pictured</a></p>

<p>I'm an amatuer coder, but I'm trying to write a code at work that will quickly replace all values in an XML. I want to replace every instance of 'linear' and 'angular' with a uniform value. I saved both the code and the XML to my desktop, and ran the code but I am coming up with the error pictured above. My code is also in the screenshot. Thanks in advance for your help! </p>