Problem With Default wallpaper GPO

Hi All,
I am working as a system administrator in a gaming company around with 90 systems.Recently my company passes rule to set default wallpaper with company logo.

So, I create Gpo called Default wallpaper and apply this settings to OU.

These setings are i changed in Gpo

1)I "Enable" the ENABLE ACTIVE DESKTOP option under User Configuration->Administrative Templates->Desktop->Active Desktop

2)I "Enable" the "Active desktop wallpaper" and set wallpaper for accessing user and give the wallpaper path like //servername/foldername/wallpaper.jpg

I gave the permissions for users to access the wallpaper.

3)I "Enable" the "Prevent Changing Wallpaper" under User Configuration->Administrative Templates->Control panel->Display


After i checking in client systems (All are windows Xp service pack2) the policy is applying with default wallpaper

But the problem is All 90 client systems have common problem...that is The background colour of desktop items have some different colour.

For this problem I change these settings

1)I try to change the settings under Desktop properties->desktop->Customize desktop->web->uncheck all options
2)check the "Lock webitems on desktop"
3)check "the Use drop shadows for icon lables" under system properties->Advanced->performance->Settings->Visual effects

But the problem is not solved....Still All icons have background colour on desktop in all client systems.

Please help me....How to resolve this issue

Thanks in Advance....