Well, I for one have not tried to install BizTalk on Windows 2000. I have a hard enough time getting installed on XP 😀 .
I could not find any information on those as well. In fact, the link on the BizTalk 2004 page on the Microsoft site was actually broken 👿 .
It is possible these were corrected in later service packs? Just a guess.
If it makes you feel any better, BizTalk 2006 is SO much easier to install.
Best of luck.