2009 problem with sp3

[puffer1]

I have loaded sp3 okay onto vista but I am unable to load it onto my XP Pro because I don't have windows sp3 installed due to problems with it.
does anyone know of a way around this.
TS 2009 works perfectly with WSP2 so why do I need WSP3 to just install an update
All my updates for windows XP are up to date