If you have an Elementalist in your group who uses AoE spells make sure he doesn't accidentally hit Carlotta because she will take damage from those attacks (and given her low level she doesn't have a lot of Health). It is a good idea to give Carlotta a decent head start and just follow her Marking Webs. Mobs will not attack her. You can of course just ignore the little spider and find the way on your own, too.