GPO from Domain dont apply on my XP !!!!!!!!!

hi I have a problem with aplying GPO from my Domain to XP workstation, there should not be problem with connection I can ping server by name and IP and GPO apply on server but not XP workstation.I’ve placed my user accounts and computers account in one OU.Any help PLEASE… !!!
server runs Windows 2003 enterprise(evaluation copy), workstation – XP Proffesional.