Since installing have you placed a .htaccess file into the flvideo folder? It seems as though non of the flv files are being able to download.

Open up you FTP and check to see if you have any flv files inside the flvideo folder. If not then your ffmpeg on the server is installed incorrectly or path is incorrect.

If there is flv files, then check for the .htaccess file and delete for the moment.

Get back to me and let me know if that fixes your issues.

Regards,
Mat.