Unity error "scripts exist in multiple locations"

I am getting this error for the files that Pro Standard Assets and Standard Assets have the same. I haven’t even used any scripts yet in the game…
Also getting this error multiple times "BCE0005: Unknown identifier:‘CheckShaderAndCreateMaterial’.

using of scripts doesn’t take sense to compiler. it compiles ALL scripts that are in Assets folder. so, you can’t have two scripts with the same name (read: two classes with same name) in project.