foiled by technology again

So I bought Iron Man 3 on DVD today, and at first my computer didn't want to play it at all, then after some reading of online how-tos I found that sometimes disabling the menus makes the DVD work with linux players. And it did become playable but jumps in places so that a bit repeats and the stuff immediately after is missing. Now I don't know whether my DVD is defective or whether it just won't work on my computer but would on a DVD player. I actually reactivated my DVD player to see, but it turns out that it got broken somehow since I last used it (it wouldn't play that DVD nor another one I tried). I guess before I return the DVD to exchange for another I'll have to check it in someone else's working DVD player, whether it glitches there too. And now I have spend 14€ on a DVD, wasted two hours on fiddling with various techonology, and still don't get to rewatch Iron Man 3. Things like this make illegal downloads so attractive... >:(