Reinstalling lippappindicator1 doesn't help. I'm using dropbox 1.6.1-1. Under 13.10 everything was fine. I'm not sure whether syncing is working.
A solution can be found in here.
To fix this Dropbox error in Ubuntu / Linux Mint / Debian, open a terminal and run the following commands:
sudo rm -rf /var/lib/dropbox/.dropbox-dist dropbox start -i
It worked perfectly for me!