Hi,
so I have the same problem too since a while and nothing happens using the small installer from adobe and the window keeps empty.Since that I did download the latest installer package set manually (60 MB) which included all three installers for IE,FF & Chrome.You can also donwload them manually from ftp server.Here a list...
Code:
https://community.webroot.com/t5/Security-Industry-News/Adobe-Flash-Player-26-0-0-137-Adobe-AIR-26-0-0-127/td-p/297062
...so GetFLV should use IE / ActiveX.If you do use Chrome / FF too then you can install all three.Just try this.
greetz