Typical Microsoft installer, it doesn’t clear the cache so OSX is using a cached version of the old .plist file in each application. Don’t worry if you don’t understand, it’s simply to fix. You need to touch each of the updated applications: Word, Excel and PowerPoint.
First, open the Applications folder then open the Microsoft Office 2011 folder. You should be able to see the Office applications there. Now open a Terminal window.
For each app (Word, Excel, PowerPoint), you type "touch " (note the space) into terminal but don’t press return. Drag Word into the terminal window and the full path of the app will complete so it looks something like this:
RobotPi$ touch /Applications/Microsoft\ Office\ 2011/Microsoft\ Word.app
Now press return. Nothing will appear to have happened. Don’t worry. Do the same and touch Excel and PowerPoint.
Now when you open each app, it should be fixed