this is normally a shell issue i think, not a KDE specific one.
try to run ldconfig, and/or start a new shell or new tab in konsole
normally, the latter ALWAYS works for me
(PS: Btw even though off-topic, this is one reason why using Gobolinux like file-layout would be an advantage, since you could just re-symlink to the version you want to use, instead of using only /usr vs /usr/local)