Version: (using KDE 4.1.2) OS: Linux Installed from: Mandriva RPMs If an icon set don't have some icons, KDE don't use default icons in replacement for missing icons.
As "default icons" do you mean the oxygen icons?
I'm not sure, but maybe this could be moved to kdelibs/kdeui. Am I right?
If this does not work, then your installation misses the Oxygen or HiColor default themes. If you want a different theme as the fallback theme, you would have to rename it to one of those names, or change the inheriting.