I think there is a little error at lib/utils/image.py!

[tissuemother]

I think line 32 and 68 have to be change from assert os.path.exists(roi_rec['image']), '%s does not exist'.format(roi_rec['image'])
to assert os.path.exists(roi_rec['image']), '{} does not exist'.format(roi_rec['image']) . If the problem just regards to python version, i am sorry. :) ;;