This hotfix will update a core system file ntdll.dll from SP1 version 5.1.2600.1106 to 5.1.2600.1177 Actually this fix was extracted from winxp SP2 (beta), not final version
the thing about this hot fix is that it probably might call or relies on certain functions only available on SP2... that's why MS don't release it as an official hotfix now.
You can still get the hot fix from MS. Just tthat you can't download it from their site. Call them and they will send you one and they said it's actually the same file I do not know about this as I got mine from that site not MS. Can't compare.
oh.. what i meant to say is NOT that MS won't release them.. i' just simply saying it's not 'official' as is release via official channels... they are making a hassle for u to get the hotfix for a reason... that's they don't want to get screwed for nothing.