Not installing on Macbook pro

so upon creating our story, writing our script, I downloaded storyboard pro to see if it was the right programs for me and my team. upon downloading it to my computer, my computer just says this… its quite upsetting. I have a Macbook pro 15 retina display. I don’t know if that helps. I have the “OS X El Capitan” version 10.11.6 I hope that helps. ill still try to find away around it, please someone help me with this issue please!

I have a maxbook pro 13 retina display running on 10.11.6 and I’m also getting the exact same message whenever I try to download storyboard pro. I was able to successfully download harmony.