cannot install firefox in the jaunty kde 4.2 RC the following file fails to install xulrunner-1.9 claiming it can't find libplds4.so.0d in the shared libraries

I would recommend filing a bug to this effect in the Ubuntu bug tracker. You are more likely to get support for package based issues such as these ( especially with Non-KDE software ) on your distribution's or the software in questions ( Mozilla Firefox in this case ) forum's.