Slide triggers that work for a next button if items have been viewed

I am trying to play the screen so that after a person clicks all three buttons and has visited three different slides, then the Next button will appear.  So the Next button is hidden to start with.  I have added visited states.  I have a slide trigger that makes the Next button normal when the timeline starts if all three buttons have been visited.  This same type of thing worked earlier in the training with pictures.  For my new slide, I first started with rectangles and then changed them to buttons.  I took the hyphens out of the text that is on the buttons.  Then I inserted pictures since my other slide that worked keyed off of pictures.  I noticed that the new pictures had a very long name so I resaved them but it contains a period.  I'm confused as to why it will not work.