I too had problems watching Treasure Planet.
I had been wanting to get a new dvd player for a couple of months, and after all of my problems with playing Treasure Planet, I took the plunge. Figured what the heck, it couldn't hurt.
I replaced my 7+ year old Toshiba with a new Toshiba dvd player from Best Buy for 99.00. Treasure Planet plays perfectly. No problems, skips....I know this might be an expensive solution, but you might also want to take you dvd to a friends or electronics store and see if it duplicates the problems your experiencing at home.
Maybe you have a older player?
Well it worked for me, if you have a newer player I don't know what else to tell you. Just thought I'd let you know how it turned out for me.