1- 将文件名中包含的“#”字符去掉。
2- 打开chm文件属性，在Security标签中，点击最下方的 Unblock 按钮。
3- Apparently this problem was introduced with one of MS security updates. I hope they fix this cause its a pain in the butt. The one most straight forward solution I found was to download this help file named MJsDiag.exe. It appears to re-register all dll's associated with help files. I was scared as hell to execute this thing but I said a prayer hoping that a million viruses/trojans wouldn't be installed, but i ran it and voila, the help files now display with no problem. I put the link to the exe below. Run at your own discretion.
http://helpware.net/downloads/index.htm#MJs
4-微软的解释: http://support.microsoft.com/kb/896054/
以上方法各自独立。
参考：http://geekswithblogs.net/evjen/archive/2006/06/29/83567.aspx