glurps,
You need to be using exploded deployment first off to get HotSync support working, also if you need a taglib class reloaded, make sure you have your application server configured to reload the new class. You can check to see if MyEclipse is actually copying out the new class file by checking the timestamp on the file when you hit Save (to see if it changes).
Also make sure you have Window > Preferences > Workbench > Automatically build, turned on.