[HerenIstarion]

Not so stolen I daresay. Similiraities are not essential - after all, almost all wizards in history were supposed to be bearded, and there were quite a few items with magical qualities, among those flying carpets, rings/cloaks/caps of invisibility etc, so ideas are just common and free to be picked up by every one. And Dobby, though not very educated, is not similar to Gollum in his essential - he's magical creature, and Gollum is human. Nor the genre - Harry is school-story, though colored with magic and with very tense plot, and LoTR is epic far more profound. And though in both books the main enemy is labelled Dark Lord, Harry and LoTr can't and must not be weighed on the same scale - you don't get heavy weight champion boxer on the same ring as a amateur feather weight, do you?
So, let the children (J.K.Rowling, with all respect, in this case) play...

disclaimer: H-I read all 4 Harry Potter books 2 times and found those most fascinating, yet still...