If you run it with the Ruby Console open there might be error messages ???
Here are the main causes of issues with this tool.
The 'red' line and the arc/curve cannot touch any other geometry, or each other. You must have the Smustard.com "progressbar.rb" installed. The object to be bent cannot be very tiny [OR gigantically large] - Sketchup/OpenGL have issues creating very small facets [<~1mm or 0.001sq"]. BUT you can scale the object x10 or x100, bend it, then scale back to suit - you will find that very small [or large] geometry can exist BUT it cannot be created. So if the object you are hoping to bend is the size of your fingernail [or a town] then you must look to scaling to save your ass...Post in the main thread to get better help π