dwifslpreproc command

Sorry, I have a problem.
When I want to run dwifslpreproc command, I am faced with this error. Can you help me to fix it?

(# dwifslpreproc sub-02_den.mif sub-02_den_preproc.mif -nocleanup -pe_dir AP -rpe_pair -se_epi b0_pair.mif -eddy_options " --slm=linear --data_is_shelled"
Traceback (most recent call last):
File “C:/msys64/home/User/mrtrix3/bin/dwifslpreproc”, line 1327, in
import mrtrix3
File “C:/msys64/home/User/mrtrix3/bin/mrtrix3.py”, line 58, in
if not imported (os.path.join (os.path.dirname (build_path), ‘lib’)):
NameError: name ‘build_path’ is not defined