river toolkit won't work

okay I recently downloaded the river tool kit but seems that when i try to put down a node it seems not to work... I have seen the tutorials, and i know i have to press 'r' but it won't work

any suggestions?

Yes, did you check the warnings? It might happen that "Shader warning in 'River Shader': No subshaders can run on this graphics card"

It is happening to me right now... and it took me several time to pay atention to the warnings...

Hold “r” then click. Make sure that the scene is selected after you click “add new node”. Select it by holding right click and looking around. Once the scene is selected, point your cursor to the desired spot, hold “r”, then left click