The whole sad story is told by Gili Bar-Hillel, who writes a blog usually in Hebrew, but in this case an English post:
Though I was not employed by Warner Bros. and not contractually obligated towards them, such was the power of this company that they were able to threaten me by proxy. As far as I was able to figure out, Warner Bros. bullied the Christopher Little Agency into bullying the various international publishers to bully their translators into retroactively waiving all rights to their translations, under the threat that otherwise the publishers would not be sold translation rights to future books in the series. This is how it happened to me: I was invited to a chat with the Israeli publisher after I had already translated the first three books in a series. He met me in a café and required me to sign a memo, which I was not allowed to read in advance or show to anyone else, and of which I was not allowed to retain a copy. I was told I must sign on the spot or the job of translating future Harry Potter books would be given to another translator. As far as I was able to understand, the memo was a promise to Warner Bros. that I would not claim trademark on any of the translated terms I had invented. I could sign or be cut off from Harry Potter forever. I signed.
It later became apparent that to Warner Bros. this memo was tantamount to a complete waiver of any and all intellectual rights I may have thought to lay claim to. When the Harry Potter films were distributed in Israel, my translation served as the basis for the subtitles and dubbing scripts of the film, without my permission or that of the Israeli publisher. I never received any compensation for this. I was never thanked or credited. In fact, the translator who was responsible for the Hebrew titles complained that her contract from Warner Bros. obliged her to use my translation.
Read the whole thing.
In comparison, Sharon Neeman had it easy - when I think of translators in Israel, I remember her song on YouTube, 5,000 words, all translated for lawyers, of course (and let me repeat that a normal day's work is nearer 2,000 words).
5000 Words (video)
Apparently there is a CD too - email@example.com for details (at least, this was the story in February 2009).