Dropbox Permissions Error

Question

I've been using Dropbox without any problems for the last 2 months.
I'm currently using Archlinux with XFCE, recently update my Distro
(that might be the problem, and it might be something else).
Whenver I start my dropbox now it gets an error and quits saying
"Couldn't start Dropbox... Permissions error"

This is the log it printed out:

pid:    1126
ppid:   1
uid:    1000
user_info:  ('user', 'x', 1000, 95, '', '/home/user', '/bin/bash')
effective_user_info:    ('user', 'x', 1000, 95, '', '/home/user', '/bin/bash')
euid:   1000
gid:    95
egid:   95
group_info: ('storage', 'x', 95, [])
effective_group_info:   ('storage', 'x', 95, [])
appdata:    u'/home/user/.dropbox'
    mode=040700 uid=1000    gid=95
parent  mode=040755 uid=1000    gid=0
dropbox_path:   u'/home/user/Dropbox'
    mode=040700 uid=1000    gid=95
parent  mode=040755 uid=1000    gid=0
HOME:   /home/user
tempdir:    '/tmp'
    mode=041777 uid=0   gid=0
parent  mode=040755 uid=0   gid=0
Traceback (most recent call last):
  File "core/authenticate.py", line 564, in authentication_thread
  File "core/authenticate.py", line 60, in handle_register
  File "core/databases.py", line 567, in load_dropbox_filecache
  File "core/file_cache.py", line 870, in __init__
  File "core/file_cache.py", line 852, in _create_connhub
Exception: Not a valid FileCache file

Answer 1

After updating Arch Linux,
pacman saved all the packages in the /var/cache/pacman/pkg directory.
Making the / partition full and so dropbox was unable to write anything and didn't work.
Simple solution was to clear the entire /var/cache/pacman/pkg directory.
though resizing the partition for future cases is also a good idea.