Thomas, you have that error when starting new world??
I used to have that error if I don't copy all the files related to the world I am trying to run. Besides being fully patched, having the latest version of CAW, you need to have both world files and folder containing layers etc in the same place. Think I managed to copy them in Program Files/EA/CreateAWorld/UserTool/Worlds (not shore if that is the path but you'll see the blank maps of Sunset Valley and Riverview there too by default) after coping both files AND folder from My Documents saved worlds, try loading world from there.
Also, it may happen that your world files are corrupted and you might want to try backed up versions created automaticaly when saving, or the one you saved yourself under different name.
Hope some of these will help.