Domain Admin Cannot create users or Reset passwords

Hi i have a weird problem with one of our domain admins,  i created his account my copying one of the other Domain Admins,

and if he logs onto the domain controller, and used AD users and computers, if he tries to create a new users, it refuses to set a password, and also if he tries to reset a password on any accounts he gets access denied.

I cannot figure out what is going wrong with this account, i have also tried creating a new account from fresh, and the same happened.

thanks

Mark