Why won't my Flash video (.flv) play online?

Web Developers: Have you uploaded a Flash video file and it won't play on the live site? It works locally on your computer, but not on the site.

Don't spend a bunch of time checking your code! You likely just need to set a MIME type for the file to play on the server. I have had this issue a few times with clients (each on various hosting providers) and made the correction by simply adding the MIME type.

Many hosting providers will offer this within their "admin control panel" or you can specify MIME type via IIS. The MIME type that should be added for Flash video is: video/x-flv The file extension is: .flv

To add Flash video MIME type in IIS, here are instructions:
1) Select the site to configure in IIS, right click and select "Properties"
2) Under HTTP Headers Tab, select "File Types"
> under the MIME Map section >select "New Type"
3) Type ".flv" as the associated extension and "video/x-flv" as the content type.
4) Select "OK" and check the site.

It should be working right away.

Check out other common MIME types 

Good luck with your project!