Hi,
Not sure what is going on there as mrregister seems to fail without an error message (are you sure you copy pasted all of the output? ERROR] seems cropped.). What is the output of:
cd /home/siying/population_template-tmp-WZ4837/
mrinfo /home/siying/sharefolder/study/template/fod_input/1.mif average_header.mif
mrstats average_header.mif
mrstats /home/siying/sharefolder/study/template/mask_input/1.mif
mrstats /home/siying/sharefolder/study/template/fod_input/1.mif
mrregister /home/siying/sharefolder/study/template/fod_input/1.mif average_header.mif -mask1 /home/siying/sharefolder/study/template/mask_input/1.mif -rigid_scale 1 -rigid_niter 0 -type rigid -noreorientation -rigid_init_translation mass -datatype float32 -rigid linear_transforms_initial/1.txt -debug &> out.txt