Account randomly locked. Windows 2000 Domain.

Scenario:
Windows 2000 domain. 4 Domain controllers.
One Exchange 2003 server.
My account has full domain admin rights.
4 (or more) times a day, it’s getting locked. I have to login as “administrator” into a Domain Controller to unlock my account.

Attempts to fix:
– Changed password
– connected to servers hunting for an application where I’d be logged in
– used the “Account Lockout and Management Tools” (http://www.microsoft.com/downloads/details.aspx?FamilyID=7AF2E69C-91F3-4E63-8629-B999ADDE0B9E&displaylang=en) with little success.

This all started when I changed my password after a few months.

How do I trace exactly what is making my account get locked?