Saw this series in the early 80's when living in Holland aged 9, in original German with Dutch subtitles i guess or perhaps dubbed into Dutch. Must have been my all time favourite TV series as a kid as I still remember the haunting theme tune and that odd little number the main character plays on his flute. I remember it as being a little sad despite the IMDb write up saying it has a happy ending, so would like to see it again as an adult. Not sure if that will happen though as it seems to be one of those things that has gotten lost in the vaults under thick layers of dust.
As I said, I don't remember many plot details except that this series, more than any other viewed as a child, has remained with me.