I've had that problem with seamonkey for YEARS. And I've used noscript for a very long time. It never helped, but I did allow some scripts for ebay to work. If I really want to buy something badly, I can persist and eventually get it to work, but very slow with all the hangups. I can't run any seamonkey version later than 2.40 though, because of my old amd processor (has the curse of no magic sse stuff:)
Could you say what script sources you allowed, if any?
Thanks!