I included the dimensions.js plugin and still have the same problem. I've been able to make other plug-ins work so I'm sure all the path stuff is right and dimensions.js is getting included ok. Neither resizeable or draggable are working.
Also the demo html files don't include dimensions.js and it doesn't appear as a file in draggable's or resizeable's dependency lists. Why are you so confident that dimensions.js would fix the problem?