hair works does not import apx.


I am trying to import apx file to the hair works viewer.
But the viewer outputs this error message below.
“hair asset does not have grouth mesh face.At least one triangle is needed”.

I selected a growthmesh and run export selection command in maya2017 up3 Linux.

Why the viewer refuses to import apx file?

The other problem is that when I create a hair works on a growthmesh, maya outputs this warnning.
“C:/Program Files/NVIDIA Corporation/HairWorks For Autodesk Maya/2017 64bit/bin/scripts/AEnxFurTemplatemel line #: [AEnvHairWorksgetRootTransform] no fullPath found on joint1.”
What does this mean?

I am using hairWorks1.2.1.