I added the missing provider parameter and updated the external version. Please try to manually update, i.e. check for update and reload the current version (although it says it's the same version)
But the request that earlier failed actually workes now. I might have fixed another issue when calling WifiRemote. I also added extra logging. Please update again and post log files if it doesn't work.
Please update again. Next time if it doesn't work: Clear MP log before test and start only the movie and no other media so I'm sure of where to look. Supply both MPiV and MediaPortal logs.
Sorry for all the iterations. To do it properly one need to debug on the WifiRemote side using your MyFilms plugin. I now send the id as a string again and not an int. Please try again and post logs aferwards....