Stuck in Mithalas Cathedral. Possible bug. (And spoilers)

[Lord Blade]

Okay, so I'm in the part of the cathedral where you're supposed to put the disc thing into the throne to open the door onward.
I've put the disc in the door... but it's not opening.
So all three thrones are "complete", yet it's still closed.

Is there any way around this? Anything to fix this?
Or am I just stuck?

Cause, I've been loving this game so far. But if there are game killing bugs in it like this...

[Azure_One]

This is not a bug. You have to sit on the throne after completing it. Notice how your cursor glows when you mouse over it.

[Lord Blade]

Yeah, I did that. Sorry, forgot to mention it.

Anyway, I got it working. I had tried loading my game. It didn't work.
But when I quit out completely, and then loaded my game, the door was open.

I don't know, odd, but at least it worked in the end.