I thought for a while that it took place in Llylgamyn as well... but then I realized that the story I read:http://www.tk421.net/wizardry/wiz6story.shtml
Was from a well-made fan page, and not from the actual manual. I've looked through the original Bane manual and the UWA one, and neither one contains a single reference to Llylgamyn anywhere in it.
So it's up to you whether or not this is Llylgamyn or not... the planet is never named, and it's left open ended for you!
Chris