I'm sure this happened to someone else years ago, but couldn't find the topic (too many similar terms in help topics)...
Do you have a save before defeating Laiken that you can reload and redo (and hope the first time was just a glitch)?
Did you try saving, loading the game in the Developer Mode version and teleporting to the battle tower throne room? There should be a cutscene conversation with Sassan in the throne room upon your return, which may or may not happen if you use the Developer Mode to get back. The return to the battle tower is also when the game lets you start using the dragon stone and dragon morph stone. The dragon stone you can try right away to go to one of the platforms; the dragon morph stone can be tested if you head to the teleporter shrine (take the elevator platform behind the throne) and going to the fjords (or back outside on Sentinel Island). Right clicking on something in your inventory should also give you the option to send it to the battle tower chest, in addition to using or destroying it.
Email support@larian.com; with your save they may be able to fix the problem. Even if the Developer Mode (if you try it) lets you continue normally, you may want to double check if not having the return to the battle tower triggered normally could cause problems later.
