"Insert citation" not working (EndNote X2)

I can’t use the ‘insert citation’ button on the top toolbar in Endnote X2. It seemed to happen when I started messing around with Endnote Web, but I have no idea how to fix this problem. (Using Word 2003, Windows Vista)

Thanks!

Go to the EndNote tools in Word. Click on the “Cite While You Write Preferences”. You should now see an Application tab. Change this back to EndNote (instead of EndNote Web).