The "Z" at the end of your search term is interesting. A few possibilities explain its presence:

While you may still find older, unofficial subtitle files online (such as on subtitle aggregator websites), they may be of lower quality or difficult to find. The 2024 Blu-ray release provides the definitive, authorized, and best-quality way to experience the film with accurate, professional English subtitles.

The film's leading actress, Bente Børsum, who played the mother, later offered a nuanced perspective on the controversy. She stated she had nothing to be ashamed of, noting, "I don't regret that film, I think it was cleanly done, there was nothing dirty about it." However, she did express a strong disagreement with how the sex scene was filmed. "The only thing I have to object to was the way was depicted the sex scene between mother and son," she said. "It sort of just became an 'ordinary' sex scene."

The most common complaint about the "Z" subtitle is that it drifts out of sync after 20 minutes. This usually happens because the "Z" release was synced to a 23.976fps version, while you have a 25fps PAL version.