Playback issues

Good morning Everyone!  I am using Articulate 2 and am having issues with a reset.  I have created a quick hands on for the learners to practice.  They select a hotspot to go to layer 2 and then a different hotspot to go to layer 3, repeat up to layer 4.  I have put a button on layers 2, 3, and 4 that says Start Over so the learner can go back to the base layer and try again.  The trigger says that anytime a user clicks the button to jump to the slide.  It works perfectly for layer 2 and layer 3 unless i try clicking on start over more than 2 times.  If I click on the button for layer 4 it takes me back to the beginning but then i cannot go through the exercise again.  My original hotspot to start the exercise does not respond.  Can anyone direct me what i need to look for to get this fixed?  Thanks.