Looking for a childrens movie from around the early 2000’s about pirates

I’m looking for this movie from I believe the early 2000’s about kids getting on a pirate ship and fighting skeletons on an island. This is what I remember about it:

There are 2 kids (1 boy 1 girl i think) who go to an attic and find a secret passage or something that takes them to a pirate ship that has a crew on it. They go to an island and are told not to touch something which they then proceed to touch. Skeletons then start attacking the crew and the kids get away. The crew gets captured and are going to be burned alive but the kids fight a mummy and get a skeleton key. I think they have to answer a riddle from a talking doorknob before they can get it though.