OS 10.4 - Need help, installer won't run

I use a macbook with tiger and recently I've had problems because the installer application just won't work. I've tried downloading and installing several different applications, like itunes and quicktime, but the installer icon appears for a second before going away. The same thing happens when I try to directly open the installer. I've already tried repairing the disk permissions, but that didn't help. I would greatly appreciate it if someone could help me out. Thank you.