Not sure there Vend - I have DX10 but forcing it to DX9 in the game using the steps below did solve my sailing issue... it really is too bad that us ATI card users are having such a hard time... I didn't need step 4 from below - just forcing the DX9 worked for me.
Now as for drivers I'm unsure about - I know mine are not the latest - so maybe I got a 'luck card' there by never upgrading them.
*note, steps below are not my credit - just put them here to spread the info so more people looking for answers may find it. Check the thread posted up there... and good luck
1) Go to Start | Programs | Accessories | Windows Explorer.
2) Navigate to C:\Program Files\Disney\Disney Online\PiratesOnline.
3) Double click on game_options.txt.
4) Make sure "state" has "working" on the line directly below it. If you see "attempted_working" change it to "working."
5) Under "api", please change the text from "default" to "pandadx9".
6) Save the file then launch the game.