Look for the file name with a hyphen rather than a colon

client/lib/item.dart

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 library category_item;
 
 import 'dart:async';
 import 'dart:convert';
 import 'dart:html' show ProgressEvent;
 
@@ skipping 392 matching lines @@
 /**
  * An [Item] that is lazily loaded.
  */
 abstract class LazyItem extends Item {
   bool isLoaded = false;
   final String previewComment;
 
   LazyItem(String qualifiedName, String name, this.previewComment,
       [String comment]) : super(name, qualifiedName, comment);
 
+  /// The name of the file/url path we'll use to retrieve this item's data.
+  String get fileName => qualifiedName.replaceFirst(":", "-");
+
   /// Loads this [Item]'s data and populates all fields.
   Future load() {
     if (isLoaded) return new Future.value(this);
-    var location = '$docsPath$qualifiedName.json';
+    var location = '$docsPath$fileName.json';
     var data = retrieveFileContents(location);
     return data.then((response) {
       loadValues(JSON.decode(response));
       buildHierarchy(this, this);
       return new Future.value(this);
     }).catchError(_loadError);
   }
 
   /// Fallback function -- if we fail to load the specific version of a file,
   /// revert to asking for an unversioned one.
@@ skipping 677 matching lines @@
 }
 
 
 bool _boolFor(String key, Map input) {
   var value = input[key];
   if (value == true || value == 'true') return true;
   if (value == null || value == false || value == 'false') return false;
   throw new FormatException("Invalid format, expected boolean key: $key"
       " value: $value");
 }