That only applies to features in a part.
The pattern menu in an assembly looks different, and does not respond to a path, only a direction.
Can you create a curve-driven pattern of something (work points, maybe) in one of your parts, then use "Feature Pattern Select" in your assembly pattern to follow the points?
I have been trying to do just that for the last hour or so.
Sometimes I can get the points to go where they are supposed to, but then it always tells me that something undetermineable is wrong.
Alttach the files here.