Video not working in Portable Prezi for Windows

I have trouble to play videos in Portable Prezis for windows. I tried both .flv videos (not working at all) and .mp4 videos (working only if the videos is included in the path and, therefore, in full screen). I tried to create the Portable Prezi both from online editor as well as from the Desktop editor.

Does this depends on video format, resolution, frame-rate or is it a general issue?

I prepared a minimal presentation with the video only, problem remains the same:

I only tried in windows 7, up-to-date, on two different machines