I ran into this same issue today. I tried the hack of rearranging the render order but no dice. Hair seems to work fine on a poly mesh, but when I limit it to an edge i get the error. Neither progressive nor bucket render solve the issue.

I want to create a design of a stitched yarn. I drew the design with splines, and then used a Sweep to give them thickness. When I apply my yarn texture it stretches the texture depending on the length of the spline. I want the texture to maintain its aspect ratio and repeat to fill the length.
I tried to rebuild the splines with MoSpline to have vertexes at equal intervals but that doesn't seem to solve the issue. How can I have a scene of many different 'ropes' of differing lenghts without the texture stretching? thank you.

FILE: yarn_01.c4d