Having had this issue in the past, I would put money on your phsyical robot being on an older version of polyscope than that of the simulator. I even made a forum post about this problem first time i had it..
Each release of Polyscope comes with its own version of the URCap API, and if you try and use a URCap that was build on a version of the API that is newer than the matching version of polyscope, you’ll find you run into this error. You can find which version if the API your URCap is built on by checking the dependencies tab of your eclipse project’s .pom