Alright, that was the bug but it seems you've already fixed it.There was a wrong locator file at some point, which would've resulted in you ending up in a spot way outside the walk patch
upon exiting the cave, but I've fixed that bug quite a while ago. Should be in all latest Patch-files.
By the way, Thanks Pieter and Captain Maggee to have fixed all the bugs this afternoon..
About the cannonl.gm in my patch, don't install it seeing it doesn't use the deck.tga.
btw : And I need your opinion about this quest in order to improve it if necessary