As you were!

[frostbite]

"Microsoft delays XP SP3 over 'compatibility issue'"

"Microsoft said on Tuesday that it is delaying the release of Windows XP Service Pack 3 because of a newly uncovered glitch"

http://news.zdnet.co.uk/software/0,1000000121,39408145,00.htm

[planecrazy.eu]

The glitch is windows XP itself :)

On a serious note, must be a big glitch or they would have just released it like usual...