Adding users to an active directory

Hey, guys.
I am running windows server 2003 Enterprise edition, and have got an active directory. but whenever i try and add a user to a domain, it comes up with the following error:
Windows cannot set the password for Test TU. User because:
The password does not meet the password policy requirements. Check the minimum password length, passwork complexity and passwork history requirements.
My password is 10 didgets long, and uses both capital and lowercase letters.
anyone know where to find the policy requirements and solve this problem?
thanks