Wireless clients unable to join domain

hi all!
this is my first question here.

we have a simle network connection in our office.
we have a Wireless router through which we all(all our laptops & desktops) are connected to internet.

We have one DC (server 2003) & is connected to the one of the LAN port of the router.

Most of our laptops are configured with static IP only.

When i am trying to join those laptops to my existing domain, i am unable to do so. instead i am getting a message that "A domain controller for the domain xyz.com could not be contacted"

i would like to mention that , fortunately i was successful in joining one of the laptop to my domain.

can anybody help me to short out this problem plzzzzzzzzzzz?????