You shouldn't need IE tab KW since AM works fine in Firefox, but go ahead and install it if you want to. Check the Tools/Options dialog and on the Content tab see if the Load Images and Enable Javascript checkboxes are checked, if not, check them and try again. If that doesn't work you may want to export your bookmarks (Bookmarks/Manage Bookmarks then File/Export) and then uninstall FF and reinstall and see if that fixes your problem (of course also reimporting your bookmarks you exported via the import function). Finally if even that doesn't work, you may want to try posting to a FF forum, for example
http://forums.mozillazine.org/index.php?c=4 which has a support forum. Good luck!