I found a post on the BizTalk Discussion Groups about SQL Server 2000 SP4 in combination with BizTalk Server 2004
Here his post :
Installed SQL Server 2000 SP4 on two development servers over the weekend
with no problems and on two production server on Monday with only slight
problems during the Analysis Server SP4 installation. The problem (bug) has
been reported to MS and they’re issuing a KB article. It’s related to the
MDAC update on servers running MOM2005.