Question
What information could be useful to understand and find out what is locking up any account?

Answer
Note: The following information is provided as reference. Troubleshooting issues with accounts locking up is usually done by the Network Administrator or Administrator for the system. Even though the issue can be related to an Altiris account, defining where or what is causing it based on their processes and recent changes can be challenging.

There are few Microsoft as well other online articles that can provide some guidance for what to look for when experiencing this type of issue. Please refer to the following articles:

Microsoft articles:
http://technet.microsoft.com/en-us/library/cc773155(WS.10).aspx -- Troubleshooting Account Lockout
http://technet.microsoft.com/en-us/library/cc776964(WS.10).aspx -- Maintaining and Monitoring Account Lockout
http://www.microsoft.com/downloads/details.aspx?FamilyID=7AF2E69C-91F3-4E63-8629-B999ADDE0B9E&displaylang=en -- Account Lockout and Management Tools
http://technet.microsoft.com/en-us/library/dd277403.aspx -- Configuring Audit Policies

Other Online articles:
http://www.windowsecurity.com/articles/Implementing-Troubleshooting-Account-Lockout.html -- Implementing and Troubleshooting Account Lockout
http://windowsitpro.com/article/articleid/98031/tools-for-troubleshooting-locked-out-accounts.html -- Tools for Troubleshooting Locked-Out Accounts
http://www.comptechdoc.org/os/windows/win2k/win2kpolicies.html -- Windows 2000 Policies
http://windowsitpro.com/article/articleid/23378/access-denied--auditing-user-account-lockouts.html -- General article

You may try some of those 'Account Lockout Examiner' tools that are available online or the tools from Microsoft:
http://www.microsoft.com/downloads/details.aspx?FamilyID=7AF2E69C-91F3-4E63-8629-B999ADDE0B9E&displaylang=en