I've got some TV series, and I made one profile for every episode. How can I manage to edit the cast with one edit process, and the datas will automatically fill 10 or 20 episodes in one process.
I mean, is there a feature, how I can use to, let's say, edit 50 profiles, to add ONE actor for all 50 profiles in one process ?  Also is there a possibility to copy one cover in 50 profiles or so ?

You can only edit one profile at a time, however Tom Gaines has made an excellent cast and crew editor that allows you to cut and paste in Profiler format, you may find it easier than creating the lists within Profiler itself.
He also has an excellent cast & crew database for a large number of TV series - you may find a lot of the hard work has already been done!
His website is http://www.tom-gaines.de/

Sorry to hear that, in that case, all I can suggest is, if you're comfortable enough working with XML, then you can edit cast and crew in notepad and paste from there - it's not easy but it still gives you a lot more flexibility than within Profiler.