The Strat uses a different format for its Boot Animation, it does not use the "bootanimation.zip" many of us consider the standard. There are 3 files altogether:
in /system/media
bootsamsung.qmg & bootsamsungloop.qmg
in /system/etc
PowerOn.wav
This is a link to one that does work and you can install it through recovery:
[EI2][Rom][Odin][Cwm]TweakStock v1.0 - RootzWiki
(Look for it in EXTRAS for "Another Boot Animation" - It's a Droid boot animation and sound file)
There are a few other phones that use this format and I've swapped in the files from those phones and they've worked for me, I'll post the links when I find them.
I would love to try to do some custom bootani's (I've done some for the Acer A500 tab) but I have not figured out how to edit the .qmg files.
As "dwitherell" posted already, this limitation is probably dictated by the kernel. Apparently other Samsung phones have had modified kernels created that allow using the "bootanimation.zip" method. Maybe someone will be able to do that for the Strat as well.