First thing is to make sure you have a valid license (Free license for students and free trial for everyone) so the Grasshopper commands operate.
In Rhino, run the command sdrZZLicenseRequest, if it fails to create an email to me, the text data is copied to Windows Clipboard. Paste (-V) the xml text into an email to firstname.lastname@example.org and I will send you back instructions. I will shortly be making improvements on the dialogs informing users that a trial license is required.
Let me know if you need help with the above steps.