The film is called Stuehl im Schnee, or something like that. (The forum you linked to had the name posted last month.) It's apparently a short film, probably based on the Natascha Kampusch kidnapping. The (very much adult) actress is Josephine Preuss. Search her name on adult video sites like Motherless.com and you'll find somewhat longer clips. If you do, the subtitle "Viele Tage Spater" means "many days later". Cheery.
