immunizing issue

I'm baffled! I'm running 1.6.2 Spybot S & D on top of Windows XP and IE8. I am using Symantec CE for Anti-Virus Software.

Sometimes when I immunize it works fine. Other times, when I go to immunize it will indicate that there is 60,000+ unprotected items that need to be immunized; yet when I click the green cross to install the immunities, they will not install. The power bar will cycle to the point of completion, but the number of unprotected items remains the same.

Ironically, if I close spybot and restart it, sometimes the 60,000 unprotected items will not immediately show up again, other times they do. Nevertheless, they do show up again; but it might take a week or two. In the interum, smaller numbers of unprotected items may be downloaded when I go to immunize, and they download and install without incident.

I have looked at the help section regarding the issue, and it states that you should try to run it as an administrator. The account I typically use does have full administrator priveleges, so I ended up running the computer in safe mode without networking through the administrators account; in addition I had all the add ons disabled and it would still not allow me to install those immunities. Likewise, and again to no avail, I have tried to uninstall and reinstall the spybot software. I do not really want to uninstall my AV software, as I ran the computer without any add-ons running. That should have allowed the unprotected items to be immunized. Obviously there is a different issue. Anyone have any ideas?