the installation of nspluginwrapper is not in the default search path of konqueror. generating a symbolic link of /usr/lib/nsbrowser/plugins/npwrapper.libflashplayer.so to /opt/netscape/plugins (there are many other possibilities) solves the issue
this works with kde 3.5, I didn't try yet with kde4
Will be fixed in 3.5.10, see bug 235758, keeping it open wrt. KDE 4.
Indeed, I think this is fixed in kde-3.5.10. Also keep in mind that netscape-flash is now adobe-flash in gentoo, and there is a native 64-bit flash in tree now. Reopen if this is still valid
*** Bug 216603 has been marked as a duplicate of this bug. ***