I had the same problems, this is what I had to do to fix everything:
First, uninstall all previous versions of the add-in (word, office, etc)
Download the 2.9c version of the add-in
Second, go to office update and install all the latest updates
Third, go to tools -> Customize -> commands -> tools and drag the "Com Add-ins" to a tool bar
Fourth, close the customize dialog
Fifth, click the COM Add-In button and hit the checkmark for AlfrescoWord2003
Sixth, tools -> Customize -> Toolbars -> and check "Alfresco"
7th, close the customize dialog box and click the Alfresco toolbar icon.