Well, this bookmarks are now Opera-Bookmarks, except that they are in the "imported"-folder!
You may create your own bookmark-structure (folders included) and move the bookmarks from the "imported"-folder to the new locations.
At last you delete the empty "imported"-folder and now you have your "genuine" Opera-bookmarks!
I presume this is a translation - it doesn't make much sense in English. We do have a German forum if you'd rather post in a language you can write better ... click in the globe icon (below, on this page) and select a language you can read better.
I've noticed this as well, for me this problem only occurs if opera itself is already in full screen.
Have you tried exiting full screen with the green button and then pressing the Netflix full screen button?
I hope it can be fixed soon, but for me this works as a temporary solution 🙂
Sorry, this is just not possible: maintaining an old version costs time (and money), and while there are many, many computer users still using Windows XP, which is why Opera decided to keep a version with security updates available for those users, there are very few on OS X 10.6.