Do you have the 3DS importer Goodie installed? It is not part of the main program installation but must be downloaded along with several other 'goodies'. With Archicad open, go to HELP>ARCHICAD GOODIES.
This will take you directly to the web page you can download these from. Follow the instructions.
MacBook Pro Retina, 15-inch Yosemite 2.8 GHz Intel Core i7 16 GB 1600 MHz DDR3
Mac OSX 10.11.1
"Implementing Successful Building Information Modeling"