You mention "can't restore to original location." Can you restore to a specified folder instead of choosing the "Original location" option?
I'm not sure why this would happen. "Argument list too long" is an odd error to get when closing a file.
I have a drastic thing you could try:
1) sudo gedit /usr/lib/python2.7/dist-packages/duplicity/robust.py
2) Find the line that looks like:
'EIO', 'ETXTBSY', 'ESRCH', 'EINVAL'])):
3) Edit it to look like:
'EIO', 'ETXTBSY', 'ESRCH', 'EINVAL', 'E2BIG'])):
4) Try again and let me know how it worked.