utilsplugin2 installation error

Hello, I am a newcomer, it’s my first post here.
JOSM seems to me not very friendly. Spent couple hours to understand how should i execute such a simple operation as splitting polygon in two using crossed polyline. No other way than to install plugin utilsplugin2 was the only solution i found at last… And guess what? It doesn’t seem to be working!

Screenshot here: https://drive.google.com/file/d/1bZ5loXnmru72E9usS9dtgD1MueWkBG9F/view?usp=sharing

Did not find a way to attach image to this post directly - one more disappointment:(