After you have accepted all changes and turned off the tracking, try making a minor edit, such as adding a character and deleting it. Does Word then let you save properly? (You shouldn't have to do this, but it is worth a try.)
The next step, if you find that you can't save any edits at all, is troubleshooting for poorly designed add-ins. See the sections that refer to Startup and COM add-ins in the article at http://support.microsoft.com/kb/921541/en-us.