Move to Desktop... script crashes with 'permission denied' error

[D. Charles Pyle]

Distribution: Ubuntu 14.04 trusty
Application: Ubuntu Tweak 0.8.7-1~trusty2
Desktop:ubuntu

Traceback (most recent call last):
  File "/usr/share/ubuntu-tweak/script-worker", line 215, in __init__
    work(file, xdg)
  File "/usr/share/ubuntu-tweak/script-worker", line 130, in move_to_xdg
    cls.do_move(source, dest)
  File "/usr/share/ubuntu-tweak/script-worker", line 80, in do_move
    shutil.move(source, dest)
  File "/usr/lib/python2.7/shutil.py", line 302, in move
    copy2(src, real_dst)
  File "/usr/lib/python2.7/shutil.py", line 130, in copy2
    copyfile(src, dst)
  File "/usr/lib/python2.7/shutil.py", line 82, in copyfile
    with open(src, 'rb') as fsrc:
IOError: [Errno 13] Permission denied: '/etc/X11/core'