Weird, I wonder what's causing it. I can't reproduce it on my computer. If you in Windows press Win+R, and paste this in: %USERPROFILE%\AppData\LocalLow\Nifflas' Games\Xenosphere it should open a folder containing the file Player.log
This file might contain info that can help me work out the cause of the crash. If you can send me the info in this file somehow, I could see if I can figure out what's causing it.
I think Unity uses the Windows API to play video though, and maybe differences in Windows versions/installations can cause this?