Q: When you use exchange tool on Exchnage 2000, when should OS of the exchange server be patched for DST? After or before you ran the exchange tool?
A: Apply Windows Server OS DST Patch first.
Please follow following patching order for DST patching...
1. Install OS patch on servers (931836)
2. Install OS patch on clients (931836)
3. Rebase calendar appointments (using TZMove (931667) / TZMove update 933146 / Exchange tool 930879)
4. Install Exchange DST patch for CDO (926666)
In organizations where OWA is not used to schedule appointments, step 4 can be performed before step 3, if desired. Please see http://blogs.technet.com/dst2007/archive/2007/03/01/should-you-run-the-cdo-update-before-or-after-rebasing.aspx for more details.