It seems that there is again problem with immunization of Firefox on Windows 98 based systems after upgrading from Spybot 1.5.2 to Spybot 1.6. SpywareBlaster freezes on start when checking for protection of Firefox. This problem does not occur on Windows XP, only on Windows 98. Maybe something should be changed in the next version 4.2 of SpywareBlaster. In the past there was a similar problem with incompatability between Spybot 1.5 and SpywareBlaster 3.5.1 which was solved with the launch of version 4.0.