Unfortunately that is not quite the case, and BTW, despite my earlier ask that you provide the exact paths, you appear to have played with the screen print showing these. That, on top of the screen shot not being clear enough on my monitor to be sure of some of the characters in the paths, means you will have to interpret the information that follows.
As I see it, you have three browsers, Internet Explorer, Firefox and what I believe may be SeaMonkey. As Internet Explorer is immunising OK, let's forget that one.
For each of the other two browsers there should be 4 immunisation items (1 for Cookies, 1 for images, 1 for Installations and 1 for Popups) for each account that the particular browser is used under.
You have two accounts using SeaMonkey, Administrator and Giovani, so there should be 8 immunisation items, and there are, and they are immunising OK. I don't use SeaMonkey so I can't be definite about this but it appears to use Hostperm.1 and so the two Hostperm.1 files for SeaMonkey are I believe at:
C:\Documents and Settings\Administrator\Dati applicazioni\Mozilla\Profiles\ notte?\cuu2nyn8.slt
and
C:\Documents and Settings\ giovanni \Dati applicazioni\Mozilla\Profiles\default\plv5m1uq.slt
Now we come to Firefox.
Version 3 by default uses permissions.sqlite, not Hostperm.1, but it will apparently work with Hostperm.1 (with the caution that this may not continue to be so in the future).
At the moment there are three sets of 4 immunisation items for Firefox, suggesting three accounts, and this also applied before you did the update to version 3.
However there are only two Profile paths for Firefox.
One at:
C:\Documents and Settings\Administrator\Dati applicazioni\Mozilla\Firefox]Profiles\qdsei8dp.default (Hostperm.1)
and one at:
C:\Documents and Settings\ giovanni \Dati applicazioni\Mozilla\Firefox]Profiles\nzw55hyq.default
Note that this latter one contains both a Hostperm.1 presumably from the original V2 installation) and a Permissions.sqlite now from the V3 installation.
Ideally (and with Spybot and all the browsers shut down) you should delete both the Hostperm.1 and permissions.sqlite in this last path, then open the firefox browser using the giovani account. Goto Tools/Options then open the Privacy Tab. In the cookie area click on the exceptions button, then add a site. It's not important what that site is, so for example you could use www.google.com and give it "allow" status. Click on close, OK, then exit Firefox. This will have created a permissions.sqlite file for the giovani account and importantly will also have primed it. You must not restart Spybot until the file has been primed as above.
If you are really going to use Firefox from the main Administrator account, then you need to do exactly the same thing there, i.e. delete the Hostperm.1 file and then regenerate and prime a permissions.sqlite file. Going on line from the main administration account is not safe practice in my opinion.
Now start Spybot. Go to the immunise screen and first undo all immunisations. This may take some time to complete as removal of immunisations from Firefox is fairly slow - be patient. Once the undo has completed, re-immunise. This should be somewhat faster.
OK now we are still left with a problem. What are the extra set of immunisation items for. Spybot thinks there are three accounts using Firefox, but there are only currently two. Was there originally another user, and is Spybot picking up on some old entries from a previous user or installation.
The only way I can see of homing in on this would be to completely uninstall Firefox, and clean out any orphaned references relating to this product. Make sure before you uninstall it you undo the immunisations for Firefox. After the cleanup there should be no Firefox items left on the immunisation screen in Spybot. When you get to that point a new install of Firefox 3 should see the problem solved. It's up to you whether you want to spend the time to do this.
Hope this helps.