I contacted Koch Media about this and got the following reply.

"Please re-start the current chapter and try again. You can choose chapters from the game's main menu. Usually you can solve problems like this by just playing the last chapter again."

I tried it and it actually worked!!! I know, it's not the best solution, but at least this way we can go on playing until this is properly addressed with a patch.

GS guys, I have the same problem. I cannot download any videos. What I usually do is download the high definition version of what I want to watch, and then keep it on my hard drive for future reference. It seems that all links are broken, and I keep getting errors like "internet explorer cannot display page".

The very reason I have a GS subscription is the HD videos, people. If I can't get that anymore, I don't have a reason to renew.