I have just talked with one of our partners in Germany and he has seen this problem randomly as well.
He had similar problems sporadically (video opened but nothing happened afterwords) but he was always able to open the video using the menu, i.e. File >Open.
Are you able to open the video using the menu?
Opening the files through the main menu always worked without a problem for him so this might be an acceptable workaround until we can reproduce and get the situation corrected.
Thank you for your collaboration.
the Telerik team