The very slow removal of immunization in SSD 1.5.1.17 is a result of the enormous Firefox file in your profile "hostperm.1". You could speed up your task, basically the removal and repair of the IE immunizations, by first unchecking all four Firefox immunizations (actually, you could uncheck the Opera ones, too, but this isn't important , especially if Opera is not installed on your system).
Alternatively, if you are a little courageous, you can navigate to your Firefox profile and open hostperm.1 with any convenient plain text editor (I use Crimson Editor, but even Notepad ought to work). If there are any lines with " 1 " in them (this means 'allow'; the white spaces are actually tabs), use an Edit selection to select all such lines; then reverse the selection so that everything else is selected, and delete! Close the file and you will find thousands of immunizations gone in SSD. There are around 4 x 7000 items involved.
Good luck!