dropbox crashed with OSError in unpack(): [Errno 1] Die Operation ist nicht erlaubt: '/var/lib/dropbox/.dropbox-dist'

Did it query you for getting root rights?

You should not have permissions issues if you are root and "dropbox update" is supposed to ask for root rights (via policy kit).

Installed it again with root rights, still the same error.

Solved the mystery. My mtu was set too high for my provider (alice), which seemingly confused dropbox.

How can i set the bug as "solved"?

I'm marking it as invalid, per your request. But there's still something weird with the error reported. It doesn't make sense to not have the right to do unpack the new version. What filesystem are you using on /var/? Do you have some unusual security policy?

Im using Ext4 on var and use the kubuntu 12.04 beta, no special security policies made.

somehow dropbox with "dropbox update" downloading themself into /var not /home dir. but when installing by packet from site its downloading .dropbox-dist into home

Skai, this is normal and expected. But as explained, it should use pk-exec to get the required rights to install itself in /var/lib/dropbox. Doesn't that work for you?

Status changed to 'Confirmed' because the bug affects multiple users.

When I do a "dropbox update", I get this:

amr@PC:~$ dropbox update
Traceback (most recent call last):
  File "/usr/bin/dropbox", line 369, in handle_data_waiting
    self.unpack_dropbox()
  File "/usr/bin/dropbox", line 379, in unpack_dropbox
    name, i, total = one_member.next()
  File "/usr/bin/dropbox", line 278, in unpack
    os.lchown(filename, os.geteuid(), os.getegid())
OSError: [Errno 1] Operation not permitted: '/var/lib/dropbox/.dropbox-dist'

But when I did a "gksudo dropbox update", everything went fine and dropbox got updated to the latest version.