how to tell KDE3.5 where to search for executeables

Hello list, the executables of KDE3.5 are now located in /opt/kde3/bin, but my KDE3 installation doesn't seam to know that. My present solution for the console was to set the PATH in my .zshrc and it worked fine until yesterday. Yesterday I tried to print a pdf via Kpdf but I got the error that cupsdoprint could not be found since it's located in /opt/kde3/bin. What can I do? How can I set the PATH variable such that KDE3 also knows it? PS: I have already thrown the PATH assignment into /etc/environment but that didn't help, too. Regards, Stefan