Video Theme installed on two sites, same host one works one doesn't

I switched to Host Upon as recommended with two accounts. I installed video theme on both accounts – mine (just to test) and my clients. Mine works perfectly and shows thumbnails every time. My clients never picks up a thumbnail. Php check on mine says ffmpeg on, on my clients is says ffmpeg off. I contacted Host Upon and they assure me ffmpeg is installed the same on all their servers and to contact the theme developer. BTW both sites have the same theme version and I have deactivated all plugins for testing. Any ideas?