Play icon just bounces in Mac dock, won't open

I am trying to send a slideshow (via Player 3.8.3) to a friend, via Dropbox. Uploads and downloads fine, but when I try to play the slideshow it just bounces in the dock and won’t open. Am I doing something wrong? Thanks!

We are using a special UNIX feature to save everything fast on the harddisk. Maybe Dropbox can’t deal with this file structure and so something is missing on the other side. Please try to make an archive of the player first (right click on the player icon in Finder and select “create archive” or “Compress…”) and put the resulting ZIP file in your Dropbox to be send to your friend.