I cant install programs or change the system time on the windows XP machine even when i log in as root or administrator
This is a normal security restriction in windows. Users that are part of a Domain controller can not do this anymore. To install software, login to your XP workstation as administrator and select to authenticate locally and not agains the domain controller. Install the software, logout and then login again with your domaincontroller user and select to authenticate against the domain controller.