First make sure that Word has at least Service Pack 1. In Word click on Word > About Word. The version must be 12.10 or higher before Word 2008 can load any commands. If the version 12.0.0 or 12.0.1 you can find the Office 2008 updates at http://www.microsoft.com/mac/downloads.
Second make sure that Word knows where to look for its startup items. In Word click on Word > Preferences > File Locations > Startup. Click on “Modify” and set the location of Startup to /Applications/Microsoft Office 2008/Startup/Word. Click on OK to save and close the preferences and quit Word.
Finally make sure that the Cite While You Write bundle file is in place. In the Finder open the hard drive and go to /Applications/Microsoft Office 2008/Office/Startup/Word. Check to see if there is a file called “EndNote CWYW Word 2008.bundle.” If the bundle is in place you can open Word and check for the EndNote commands. If the bundle file is not in the Word folder you should be able to find a copy of “EndNote CWYW Word 2008.bundle” in /Applications/EndNote X5/Cite While You Write. You can copy and paste the file into the Word folder.