how to fix ''dpkg was interrupted you must run 'dpkg--configure-a' to correct problem

During uninstal of Nautilus, (as I couldnt get it to run) using the package manager it hung whilst downloading dropbox, why it was doing tha I dont know!
I had to force quit the package manager. I did a restart and opened the pakage manager and had the alarm to run this command from a terminal. When I did so, it hung again, this is copy of Terminal after waiting 20 mins:-

sudo dpkg --configure -a
[sudo] password for graham:
Setting up caja-dropbox (0.7.1-3+maya) ...

Downloading Dropbox... 100% o share and store your files online. Want to learn more? Head to http://www.dropbox.com/

I did a restart and tried again with the same result

Now I cannot use thye update manager, or the package manager as they always alarm the same, asking sudo dpkg --configure -a to be run
Some help would be appreciated