Issue: the webwalker attempts to use the Underwall tunnel between Draynor and Port Sarim, this requires the completion of the Draynor&Lumby medium diary.

Position of the Object/NPC: See img

Position of where you will start: See img

Position of where you will end: See img

Name of NPC/Object: "Underwall tunnel"

Name of NPC/Object action: "Climb-into"

Quests required (if applicable): Medium tier of the Lumbridge and Draynor Diary

F2P or P2P: P2P

Additional (if applicable):

The following test code will attempt to walk from Draynor to Port Sarim, it will use the tunnel and fail.
Start location: (3072, 3260, 0)
 

        WebWalkEvent event = new WebWalkEvent(new Position(3059,3262,0));
        PathPreferenceProfile ppp = new PathPreferenceProfile();
        ppp.setAllowTeleports(true);
        event.setPathPreferenceProfile(ppp);
        execute(event);

Thanks for reporting this link bug. 

Looks like you're in the same boat as Khaleesi right now. Once again, no idea why it was added if we don't have the API written for Achievement Diaries. 

Fixed in .89.