Automatically move to next slide after quiz question

First you have to understand the design of quiz slides. The Submit button triggers a two-step design process:

1. User clicks the Submit button and the feedback messages appear. Since Captivate cannot know how much time the learner needs to read those messages (you can simply attach the audio to the messages), CP waits for an action of the learner that indicates that ye has read or listened to the message, than he
2. needs to click on the slide or press Y to continue. At that moment only the playhead is released and the actions 'Success' or 'Last Attempt' are done (except if there is still an attempt on Question level, where the learner will be able to change the answer and the Retry message appears).

Tell me how you will estimate how much time is needed for reading the messages if you want to skip the first step, please? Than I will be able to offer you one or more possibilities but it will mean a lot more work.

BTW I moved your question to the Quizzing subspace.