or...
Press Alt+F2, and run korgac or KOrganizer. Once the system tray icon is there again, right-click on it and set it to Start Reminder Daemon at Login.
OS: Kubuntu 6.06 LTS (Dapper Drake) | KDE 3.5.3
Computer Specs: AMD Sempron 2200 1.5Ghz | VIA KM266 Pro 8235 chipset | nVidia GeForce MX 4000 128MB DDR-RAM 32-bit AGP 8x