Photoshop elements 11 won't recognize camera device.

I recently purchased a used Imac 2008 version 10.11.6. I downloaded photoshop elements 11 onto computer which went successfully I believe. I proceeded to plug my nikon d3100 camera into computer and when I went to elements organizer to load pictures from camera it said no device found. Iphoto which was already loaded onto imac did download pictures from camera. I tried reloading photoshop again but still the same problem. Is there anything I can do to fix this issue? Thanks, Gary