It is hard to say what is causing that failure, so would you try a couple of things?
1. Try it without the quotes:
xvfb-run -a vglrun -d egl 3dTcat \
-prefix Temp.nii \
Zero_dataset.nii \
$file_paths
2. Try it from the subdirectory. Forget the ROI order, this is just a test...
cd /project/..........THAT_PATH_TO.../Yeo7N_1000ribbon
xvfb-run -a vglrun -d egl 3dTcat -prefix Temp.nii Zero_dataset.nii [0-9]*.nii
Do these succeed or fail?
Thanks,
- rick