file loading (e.g., 'volume.nii' in lesson 13a) does not work

[alenauus]

Hello,

I've been trying to run xtk lesson with my own files (on my computer or online) but loading external files does not work (black screen). All examples seem to work only with the files from http://x.babymri.org/*** .

Do I need to install some additional libraries

E.g., volume.file = 'http://www.cogitatum.org/mprage003.nii.gz'; - leads to errors ..

Thank you!

Alena