You cant run 32-bit SQL 2000 inside native 64-bit Itanium Server (even with SQL 2000 sp4)
Your are required to get the MS SQL 2008 64-bit /MS SQL 2005 64-bit.
You may run 32-bit SQL 2000 ent SP4 on Xeon EMT64 thru WOW64 emulation, i believe there is performances trade off & RAM limitations on SQL. (I'm asumed u re using Windows 2003 R2 x64 edition) Strongly not recommend.
Your choice will be below , since SQL 2008 rtm still new =)
SQL 2005 EE in 64bit native on IA64
SQL 2005 EE in WOW64 (32bit emulation) on x64
SQL 2005 EE in 32bit on x86
More info about theMS SQL2000 SP4 can be found here
http://support.microsoft.com/kb/898042
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