Protheus,
Make sure you do not have any automated processes that are name and passcode dependant. In my case, I had an archiving process that ran every fifteen minutes, but when setting up, it asked me for user name and passcode, so I used mine. But a month later I had to change my usr name and passcode for security reasons, but the archive was still using the old logon and kept locking up every 15 minuts.