A bug on video interface example

Hi,this interface is great but I have a bug with it. I put it on my website : http://www.vrtv.fr but when we drag the time position while the video is not entirely loaded, it does anything. Does anyone have a solution for it ? I've tried to fix it bug but I could'nt

Thanks Klaus, unfortunately I don't think the problem comes from the video. Indeed, it's doing it with every videos encoded by different ways.
Moreover, with the same videos, if I use the interface published here I have no problem anymore. So you'll say I have to use this interface, but I prefer the look of yours . So you'll say I have to fix the problem comparing the scripts of the 2 interfaces, but I tried and I haven't managed to do it .
So I'm crying in your forum, hoping someone will help me.