Dropbox nicht mehr in Taskleiste und keine Synchronisation

Same here: dropbox.app doesn't start and delivers following report:

bn.BUILD_KEY: Dropbox
bn.VERSION: 3.10.7
bn.DROPBOXEXT_VERSION: failed
bn.is_frozen: True
pid: 7676
ppid: 137
uid: 502
user_info: pwd.struct_passwd(pw_name='petrovic', pw_passwd='********', pw_uid=502, pw_gid=20, pw_gecos='Petrossowitsch', pw_dir='/Users/petrovic', pw_shell='/bin/bash')
effective_user_info: pwd.struct_passwd(pw_name='petrovic', pw_passwd='********', pw_uid=502, pw_gid=20, pw_gecos='Petrossowitsch', pw_dir='/Users/petrovic', pw_shell='/bin/bash')
euid: 502
gid: 20
egid: 20
group_info: grp.struct_group(gr_name='staff', gr_passwd='*', gr_gid=20, gr_mem=['root'])
effective_group_info: grp.struct_group(gr_name='staff', gr_passwd='*', gr_gid=20, gr_mem=['root'])
DYLD_LIBRARY_PATH: None
cwd: u'/Applications/Dropbox.app/Contents/Resources'
     real_path=u'/Applications/Dropbox.app/Contents/Resources'
               mode=040755    uid=502    gid=20
     parent    mode=040755    uid=502    gid=20
HOME: u'/Users/petrovic'
appdata: u'/Users/petrovic/.dropbox'
         real_path=u'/Users/petrovic/.dropbox'
                   mode=040755    uid=502    gid=20
         parent    mode=040755    uid=502    gid=20
dropbox_path: u'/Users/petrovic/Dropbox'
              real_path=u'/Users/petrovic/Dropbox'
                        not found
              parent    mode=040755    uid=502    gid=20
sys_executable: '/Applications/Dropbox.app/Contents/MacOS/python'
                real_path='/Applications/Dropbox.app/Contents/MacOS/python'
                          mode=0100755    uid=502    gid=20
                parent    mode=040755    uid=502    gid=20
trace.__file__: '/Applications/Dropbox.app/Contents/Resources/lib/python2.7/site-packages.zip/dropbox/client/ui/common/boot_error.pyo'
                real_path='/Applications/Dropbox.app/Contents/Resources/lib/python2.7/site-packages.zip/dropbox/client/ui/common/boot_error.pyo'
                          not found
                parent    not found
tempdir: u'/var/folders/b5/qq8wvd8s0wz5q473m66qhjpm0000gp/T'
         real_path=u'/private/var/folders/b5/qq8wvd8s0wz5q473m66qhjpm0000gp/T'
                   mode=040700    uid=502    gid=20
         parent    mode=040755    uid=502    gid=20
Traceback (most recent call last):
  File "dropbox/client/main.pyo", line 3572, in main_startup
  File "dropbox/client/main.pyo", line 1676, in run
  File "dropbox/client/main.pyo", line 783, in startup_low
  File "dropbox/client/multiaccount/instance_database.pyo", line 849, in __init__
  File "dropbox/client/mapreduce.pyo", line 69, in __init__
  File "dropbox/client/mapreduce.pyo", line 110, in new_user_key
  File "dropbox/keystore/keystore_posix.pyo", line 120, in store_versioned_key
  File "dropbox/keystore/keystore_posix.pyo", line 103, in store_key
  File "dropbox/keystore/keystore_posix.pyo", line 91, in _save_dict
OSError: [Errno 13] Permission denied