title: Dart: "Invalid argument(s): Illegal character in path" when building on Windows
body: <p>The offending line in my index.html file reads </p>
  
  <pre><code>&lt;script src="main.dart" type="application/dart"&gt;&lt;/script&gt;
  </code></pre>
  
  <p>The error report is:</p>
  
  <pre><code>Build error:
  Transform polymer (PolymerBootstrapTransformer) on myproj_frontend|web/index.html threw error: Invalid argument(s): Illegal character in path
  dart:core/uri.dart 855                               Uri._checkWindowsPathReservedCharacters
  dart:core/uri.dart 956                               Uri._makeWindowsFileUrl
  </code></pre>
  
  <p>The entire path to the project is</p>
  
  <p><code>D:\Projects\MyProj\MyProj_Project</code></p>
  
  <p>I'm building from command line on Windows 7 using Dart VM version: 1.16.0</p>
  
  <p>I honestly have no idea how to continue diagnosing or fixing this.  <em>Any</em> help would be greatly appreciated.</p>