Hi Stephen Murphy,
Did you add app_type: rhoelements in your build.yml file?
I tried the same code that you have posted, it works for me, If you don't include rhoelements in your build.yml file you may get this error.
I think this explains it. Also, I did not realize that the Gestures API requires a license. I am evaluating Rho for my company, and do not currently have a license, so that may be the rest of my issue.
Thanks for the help.