Please upgrade to the new Spybot - Search & Destroy 1.6:
You will find links to several download locations for this new version on our web site:
http://www.safer-networking.org/en/mirrors/index.html

If you are not immunizing with full administrator rights, Spybot-S&D might not have permission to immunize all user accounts.

If you are using Windows Vista, you should also read this FAQ entry about getting Administrator rights under Vista.

Some users have reported that they use SpySweeper or SpywareBlaster and shutting them down solves the problem. ZoneAlarm might also block the global hosts. If you go to Firewall in ZoneAlarm on the left and then the main tab in the upper right then go down to the advance button and click on it you will see under General setting "Lock Hosts file".

Further please try the following:

Open Spybot -> Immunize -> under Windows uncheck Global (Hosts). Go into Spybot -> Mode -> Advanced Mode -> Tools -> Hosts file -> and then click on the "Add Spybot S&D hosts list" button. Go back into Spybot -> Immunize

The problem that not all global host entries have been immunized has also been discussed in our forum:
http://forums.spybot.info/showthread.php?t=18122&highlight=immunize+global
http://forums.spybot.info/showthread.php?t=19314&highlight=immunize+global
http://forums.spybot.info/showthread.php?t=17913&highlight=immunize+global