Run GPresult on the client.
Also, try rejoining those computers to the domain.
See if that does it.
Finally, make sure they're in the OU where the GPO is linked.
I have recently made a change to one of my Group policies the policy was set to enable the Windows XP firewall with exceptions this was then changed to Disable firewall.
While this has worked well on the majority of machines it has not worked on all. Has anyone got any ideas on what to do next?
Run GPresult on the client.
Also, try rejoining those computers to the domain.
See if that does it.
Finally, make sure they're in the OU where the GPO is linked.