[Plugin: Viper's Video Quicktags] FLV dissapeared

Likely it is due to this GPL conflict.

http://www.viper007bond.com/2012/04/12/jw-flv-player-removed-from-my-vipers-video-quicktags-plugin/

But you can do something about it:

If you wish to continue to use the player to embed .flv and .mp4 files after upgrading to version 6.4.0 of my plugin, you will need to download this ZIP file and extract it to your wp-content folder, resulting in /wp-content/jw-flv-player/player.swf.

It’s difficult to see the link, but it’s there on that page at “this ZIP file”.