YouTube problem

Dear all, 

I am facing following problem. 

Users has installed Web Endpoint and going  through Web Cloud for YouTube websites. 

After watching 1:15 min of the below URL, movie suddenly stops and is not moving further. 

http://www.youtube.com/watch?feature=player_detailpage&v=SI_5brKL89g

Maybe someone have seen or have had  such problem ? 

Thanks for reply. 

Best Regards,

zurawdom