Please refer to
  https://bugs.kde.org/show_bug.cgi?id=209903

  http://www.davidfaure.fr/2009/klauncher_mac.diff

Index: klauncher.cpp
===================================================================
--- kdelibs-4.3.3/kinit/klauncher.cpp	(revision 1034932)
+++ kdelibs-4.3.3/kinit/klauncher.cpp	(working copy)
@@ -1144,6 +1144,12 @@
     kDebug(7016) << "KLauncher: launching new slave " << name << " with protocol=" << protocol
      << " args=" << arg_list << endl;
 
+#ifdef Q_WS_MAC
+    arg_list.prepend(KLibLoader::findLibrary(name));
+    name = KStandardDirs::locate("exe", QString::fromLatin1("kioslave"));
+    arg_list.prepend(name);
+#endif
+
 #ifdef Q_OS_UNIX
     if (mSlaveDebug == arg1)
     {
@@ -1154,8 +1160,10 @@
     }
     if (mSlaveValgrind == arg1)
     {
+#ifndef Q_WS_MAC
        arg_list.prepend(KLibLoader::findLibrary(name));
        arg_list.prepend(KStandardDirs::locate("exe", QString::fromLatin1("kioslave")));
+#endif
        name = QString::fromLatin1("valgrind");
        if (!mSlaveValgrindSkin.isEmpty()) {
            arg_list.prepend(QLatin1String("--tool=") + mSlaveValgrindSkin);