Hi Rupy -
Currently there is nothing that you can do to recover the level. We are working on a fix to this problem, but I cannot say with any certainty that you will ever be able to recover the level.
Just remember you can have multiple Matinee Actors in a level just do not duplicate one. Create new each time, then go into each actor and copy tracks to the newly created one.
Again Thank you for your patience and helping to track down this issue,
Eric Ketchum