今天用MSDN查个东西，居然显示如下页面：
File Association
Windows has the following information about this Protocol. This page will help you find software needed to open your file.
Protocol Type: res
Description: UnKnown
Windows does not recognize this Protocol.
You can search the following Web site for related software and information:
Windows Live Search
Have questions? See these Frequently Asked Questions.
安装后第一次使用，郁闷，看了下好像是什么协议不识别。Google了下，问题解决。
方法：在“运行”里输入：regsvr32 "C:/Program Files/Common Files/Microsoft Shared/Help/hxds.dll"
确定，弹出如下框，dll注册成功。
再去MSDN，ok了。特记下。