The security update has been reported to work on any INTEL SSE3 machine.
AMD is broken, since it replaces some of the files (Finder) that have been patched.
You need to be sure that you are running r2d2,
which should be the case if you installed latest 10.4.8 JaS DVD.
If you are not sure, run the command kextstat under Terminal,
and see if r2d2.kext is listed/loaded.
If you are running the last modded from source 10.4.8 kernel,
you don’t need r2d2.kext anymore, it is integrated in kernel.