FLV Splitter

The playback of video and audio files involves more components than it would seem at first glance. If the media player software which is used for the job doesn't have its own set of codecs and filters, they should be installed separately onto a system, to ensure the smooth reproduction of the loaded media files.
When it comes to Flash videos, particularly the FLV container format files, things are quite simple because most Internet browsers have dedicated plugins, that are designed to load this type of online content. Nonetheless, if the movies are stored locally on a computer and someone tries to open them directly, certain components must be present onto that system in order to play FLVs.
If you are using a DirectShow-based player, like the one built-in your Windows OS (Windows Media Player), the appropriate splitters and decoders have to installed for you to be able to open FLV movies. If there is none, you could try FLV Splitter which is especially designed for the above mentioned purposes.
Even if doesn't come with a proper installer, this DirectShow splitter can be integrated in the operating system using the Regsvr32 command, followed by the exact location of the AX file. This procedure can be carried out either from the command-line, or by simply bringing up the 'Run' command from the Start Menu or by pressing Win+R to have the dialog box displayed onto your screen.
This simple routine, if completed properly, will result in the FLV splitter filter being recognized and used by all applications that require DirectShow filters to decode and play this specific Flash video format.
All in all, FLV Splitter can prove to be just the component you are missing in case you can't get those FLVs playing onto your computer, so it's worth taking that minute to unpack and register the DirectShow filter.