Add user in active directory WIN2003

Hi,

I am facing problem to create a new user in active directory on server 2003. when i create a new user with login and password then first time that usr can login from client pc but second time he can not login and screen shows the "method you are using is now allowed...".
my client pc has window vista business.
local policy of client pc has admin,usr,guest but when i have connected to domain than i have seen it local policy has only admin no usr and it did not highlight the add button so that i can add usr. can any one help me what is wrong with my active directory usr seting. thanks
sag