Well, I tried this and it worked for me. I hope it will be the same with you:
sudo mkdir data
sudo chown <youruser> data
Where youruser is, obviously, different than root.
Now type this:
sudo blkid | grep UUID
You will be able to identify UUID and TYPE of your filesystem where dropbox folder is stored.
Copy the choosen pair somewhere. Now edit fstab
sudo gedit /etc/fstab
and append at the end of the file something like this:
UUID=yourUUID /media/data yourTYPE defaults 0 0
Ok. Now, last step:
Check if is really stopped. If it isn't, kill it (You can use
rm -rf ~/.dropbox
and restart dropbox
It will be start syncing files from the internet.