4.6.6 is the most recent update for Ambitions.
Beddy, I was having this issue too. I backed up my game files, then un-installed Ambitions. THEN I updated my EADM (EA Download Manager). Then restarted my computer and re-installed Ambitions. Then I restarted and updated through The Sims 3 Launcher. Now it doesn't show the message every time that I need to update my game!
Some people have said that simply updating the EADM helps that message go away. I would try updating the EADM and restarting first, it may make that message go away