Reading Xml files, InvalidCastException

Hi, I know there's lots of questions out there about invalid cast exceptions, but I couldn't find any that are cluing me in enough on my problem. I got this script from the forums for adding multiple language support, and its a bit more advanced than my current skill level. The line from SetLanguage()

  var xmlItem = (XmlElement)elemEnum.Current;

is giving me the InvalidCastException runtime error when I call the function from another script like this:

 langClass.setLanguage (Path.Combine (Application.dataPath, currentLevel + currentLanguage + ".xml"), currentLanguage);

Here's the whole script for your reference. If I can post anything else to help, please let me know.

  using System;
     using System.Collections;
     using System.IO;
     using System.Xml;
      
     using UnityEngine;
      
     public class Lang
     {
         private Hashtable Strings;
      
         public Lang ( string path, string language, bool web) {
             if (!web) {
                 setLanguage(path, language);
             } else {
                 setLanguageWeb(path, language);
             }
         }
      
         public void setLanguage ( string path, string language) {
             var xml = new XmlDocument();
             xml.Load(path);
          
             Strings = new Hashtable();
             var element = xml.DocumentElement[language];
             if (element != null) {
                 var elemEnum = element.GetEnumerator();
                 while (elemEnum.MoveNext()) {
                     var xmlItem = (XmlElement)elemEnum.Current;
                     Strings.Add(xmlItem.GetAttribute("name"), xmlItem.InnerText);
                 }
             } else {
                 Debug.LogError("The specified language does not exist: " + language);
             }
         }
      
         public void setLanguageWeb ( string xmlText, string language) {
             var xml = new XmlDocument();
             xml.Load(new StringReader(xmlText));
          
             Strings = new Hashtable();
             var element = xml.DocumentElement[language];
             if (element != null) {
                 var elemEnum = element.GetEnumerator();
                 while (elemEnum.MoveNext()) {
                     var xmlItem = (XmlElement)elemEnum.Current;
                     Strings.Add(xmlItem.GetAttribute("name"), xmlItem.InnerText);
                 }
             } else {
                 Debug.LogError("The specified language does not exist: " + language);
             }
         }
      
         /*
         Access strings in the currently selected language by supplying this getString function with
         the name identifier for the string used in the XML resource.
      
         Example:
         XML file:
         <languages>
             <English>
                 <string name="app_name">Unity Multiple Language Support</string>
                 <string name="description">This script provides convenient multiple language support.</string>
             </English>
             <French>
                 <string name="app_name">Unité Langue Soutien Multiple</string>
                 <string name="description">Ce script fournit un soutien multilingue pratique.</string>
             </French>
         </languages>
      
         JavaScript:
         var appName : String = langClass.getString("app_name");
         */
         public string getString (string name) {
             if (!Strings.ContainsKey(name)) {
                 Debug.LogError("The specified string does not exist: " + name);
              
                 return "";
             }
      
             return (string)Strings[name];
         }
      
     }