Windows 2003 server-cannot implement a wallpaper

Hello all,
I just installed Windows 2003 server here at our school. As a test for future consideration, I am trying to push out a wallpaper background to my win 2000 workstation. I have created a GPO and specified the JPG file on the server. Now here is the interesting part, when you go to the workstation and right click the desktop for background, the wallpaper is highlighted but will not display. I have enabled Active desktop and the wallpaper setting in the GPO. I have also tried a .BMP file and the result is the same. Same prob with xp pro workstations as well. Were am I going wrong?
Thank You