XP Domain user loginLogin

Hello Everyone,
I’m upgrading the PCs in the network to Windows XP, and the user account I’m using in installation is mine which it is belong to Administrators group in NT4 Domain, and till now everything is going OK,
And after finishing installation I can login in my account, but when I add another domain user accounts in the computer by using the user accounts in control panel, I could?nt login to the computer by using this user accounts, so anybody know why?