That's good. I wondered if you were using an old, unsupported version because that's what's in your profile. Running an old version can cause this error.
In this case, it is probably because there's a mismatch between the token on your machine and the one on the server.
First, open a terminal and run
This makes sure there are no Ubuntu One processes running on your machine. If you get some "no process found" messages, it doesn't matter.
killall ubuntuone-login ubuntuone-preferences ubuntuone-syncdaemon
Open Passwords and Keys and remove the password/token for Ubuntu One.
Browse to the Ubuntu One web interface and login. Under "My Account", there's a section showing Authorized Machines (or similar). Find the entry that relates to your machine and remove it.
Then try restarting the Ubuntu One client and connecting to the server. It should go through an authentication routine again and create a new token.