You didn't specify that the arrow should only appear after they clicked the Submit button. I explained several possible tweaks in this blog post:
Question Question Slides in Captivate - Captivate blog
Can you please explain clearly what you want. I offered you an easy fix to enable the user to click on an arrow instead of clicking on the slide, but that seems not to be what you want. Please!
As I have mentioned multiple times, Quiz slides have very strict rules, if you want to change anything you need to have a good knowledge of the normal work flow, advanced/shared actions and sometimes variables.