Hi,
 I want to create thumbnails of flv files on the fly , i think i need to install ffmpeg, but how to install it on our local machine as well as linux server. and how to use ffmpeg in programming to create thumbnail.

To install and use FFMpeg.exe on Windows with IIS check here -

Installing FFMpeg on Windows
http://phpfoxguide.com/index.php/200...indows-server/

If you are looking for options to create a video gallery for your site then try out ready applications as it will save your time.
One such product can be found here -

http://www.flashtuning.net/component...allery_12.html