Seems like the Raspberry Pi needs to be setup first, you can do that by performing following steps,
* Go to "Home" tab in MATLAB
* Select "Manage Add-Ons" from "Add-Ons" dropdown
* Click the gear icon at the end of "MATLAB Support Package for Raspberry Pi Hardware"
* Follow the Hardware Setup process
* Reboot the Raspberry Pi and create object in MATLAB.
MATLAB Hardware Team