Machinarium uses Flash Player 10. Maybe that's what the problem is. You can try running the game with the latest version of Flash Player. You can download Adobe's standalone Flash Player 15 Projector here:
http://fpdownload.macromedia.com/pub/flashplayer/updaters/15/flashplayer_15_sa.dmgOnce it's downloaded, you'll have to perform a couple of additional steps:
1. Open the folder which contains Machinarium and Control-click on the Machinarium application.
2. Select Show Package Contents and then open Contents/Resources.
3. Locate the movie.swf file and move (or copy it) so that it sits right alongside the application for Machinarium.
4. Control-click on the movie.swf file and choose Open With, and from the list find Flash Player 15.