Problem with Outlook Backup in Vista

I have been using Outlook 2007 in Vista. I had the Outlook Backup add on installed, but suddenly noticed it had disappeared from the file menu. I tried to reinstall it, but was told it was on and had to be uninstalled first. I tried this, in the hope that a reinstall would restore the backup line on the file menu, but even after uninstalling and reinstalling several times, there is still no sign of any place to click on for backup in the file menu. I have checked that the backup is installed in the program and features menu, but does not seem to appear on Outlook. Any information as to what is causing this and how to fix it would be appreciated. Thanks.