E文的文章，不过很简单，就不翻译了。

Windows 2003 Server does not stream FLV videos

Please be aware that these steps do not resolve any issue with Macromedia Flash, but are a configuration step for Microsoft Windows 2003 and Microsoft IIS Server 6.0. Any difficulties in executing those instructions or any errors that may arise from modifying your system settings should be addressed to Microsoft. For more details, please refer to your IIS documentation.
1.On the Windows 2003 server, open the Internet Information Services Manager.
2.Expand the Local Computer Server.
3.Right-click the local computer server and select Properties.
4.Select the MIME Types tab.
5.Click the New... button and enter the following information:
6.Associated Extension box: .FLV
7.MIME Type box: flv-application/octet-stream
8.Click Ok.
9.Restart the World Wide Web Publishing service.

其实就是在IIS的MIME类型中加入关联扩展名：.flv，内容类型：flv-application/octet-stream。