Whenever you install or reinstall a script you must restart Sketchup [unless you are Ruby-savvy enough to use load "xxxxx.rb" !]
You can 'bend' any geometry as long as it's in a group or a component-instance.
As Gai says you must have a line and an arc and the grouped geoemtry, all correctly oriented - as clearly explained in the thread...
As for bending 3d Text... there are already some posts about that - read through the thread.
Any 3d Text is only a lot of geometry - the 2d outline of each letter is extruded into a 3d object...
So all you need to do is to group all of this geometry first, and then proceed as with any other shape-bending...