Question : Group Policy not applying to XP Machines

Hi

I am trying to deploy a group policy.
its a registry setting.
For some reason this setting is only being applied to Windows 7 machines and some XP machines. Same user and the computer accounts are in the same OU. I just loaded a new machine (XP Pro) and it is doing the same thing.  i tried gpupdate /force and it just says to reboot for the settings to take effect.
when I run gpresult it shows the group policy has applied but I dont see it.

Domain Controllers Windows 2008 R2
Domain Mode (2k8)
Group Policy:
User Configuration (Enabled)hide
Preferenceshide
Windows Settingshide
Registryhide
Wallpaper (Order: 1)hide
Generalhide
Action Update
PropertiesHive HKEY_CURRENT_USER
Key path Control Panel\Desktop
Value name Wallpaper
Value type REG_SZ
Value data \\ag-backup\NETLOGON\desktop.bmp

Commonhide
OptionsStop processing items on this extension if an error occurs on this item No
Run in logged-on user's security context (user policy option) No
Remove this item when it is no longer applied No
Apply once and do not reapply No

-------------------------------------
I recieved this error one 2 machines in the event log but its also not happening on all machine.

Event Type:      Warning
Event Source:      Group Policy Registry
Event Category:      (2)
Event ID:      4098
Date:            2010/06/23
Time:            11:04:39 AM
User:            NT AUTHORITY\SYSTEM
Computer:      XXXXXX
Description:
The user 'Desktop' preference item in the 'Desktop Wallpaper {938E027F-24B3-452C-ABA4-8646F7AE2865}' Group Policy object did not apply because it failed with error code '0x80070057 The parameter is incorrect.' This error was suppressed.

For more information, see Help and Support Center at http://go.microsoft.com/fwlink/events.asp.
Error



Please Assist and let me know If you need any furture information. I hope the question is clear.

Answer : Group Policy not applying to XP Machines

Do the xp machine that its not being applied to have the group policy client side extensions installed.

http://www.microsoft.com/downloads/details.aspx?FamilyId=249C1AED-C1F1-4A0B-872E-EF0A32170625&displaylang=en