Alright ! Thank you for this advice! It works now!
However, while it calculated the population_template I got this new Error message:
mrregister ./fod_input/AKTIV2240A.mif linear_template2.mif -force -rigid_init_matrix linear_transforms_2/AKTIV2240A.txt -mask1 ./AKTIV2240/mask_input/AKTIV2240A.nii -rigid_scale 0.8 -rigid_niter 100 -rigid_lmax 4 -type rigid -datatype float32 -rigid linear_transforms_3/AKTIV2240A.txt
mrregister: [ERROR] Error allocating memory for scratch buffer
Here is an image of the debugging:
I do the processing on a Grid-Server (cluster).
I already checked this post, but I do not really understand the solution: http://community.mrtrix.org/t/mrregister-error-error-allocating-memory-for-scratch-buffer-while-executing-population-template-command/403
Thank you for any kind of help!
Best
Max