It looks as if there are some strange problems in the mozilla component registry in the ebuild of mozilla 1.6. Apparently, if galeon is installed, galeon components get registered and requested for jobs such as adding helper apps, which causes the helper app dialog to fail at a number of points. Please see http://bugzilla.mozilla.org/show_bug.cgi?id=234590
I applied the standard Microsoft help desk 3R's solution ("Remove, Reboot and Reinstall"), only since this is Linux, it's a 2R's solution since a reboot isn't required :-) I unmerged mozilla in gentoo _first_ before rebuilding, and explicitly deleted (rm -r) /usr/lib/mozilla since the component registry wasn't removed by the unmerge. After rebuilding mozilla, all the problems I observed are gone except for the issue with radio buttons. Since this bug report describes a problem specific to the helper apps dialog which seems to be fixed by the rebuild, I'm marking it resolved. I'll file another one regarding the radio button issue.
