title: Error when using Esapi validation
body: <p>I hope someone could help me with some issue.</p>
  
  <p>I'm using OWASP ESAPI 2.1.0 with JavaEE, to help me to validate some entries in a web application. At some point I needed to validate a Windows file path, so I added a new property entry in the 'validation.properties' like this one:</p>
  
  <pre><code>Validator.PathFile=^([a-zA-Z]:)?(\\\\[\\w. -]+)+$
  </code></pre>
  
  <p>When I try to validate, for example, a string like "C:\TEMP\file.txt" via ESAPI, I get a ValidationException:</p>
  
  <pre><code>ESAPI.validator().getValidInput("PathFile", "C:\\TEMP\\file.txt", "PathFile", 100, false);
  </code></pre>
  
  <p>Alternatively, I also tried the <em>java.util.regex.Pattern</em> class to test the same regular expression with the same string example and it works OK:</p>
  
  <pre><code>Pattern.matches("^([a-zA-Z]:)?(\\\\[\\w. -]+)+$", "C:\\TEMP\\file.txt")
  </code></pre>
  
  <p>I must say that I added other regex in 'validation.properties' and worked OK. Why this one is so hard? Could anyone help me out with this one?</p>