Default user Profile unable to display wallpaper

I have created a default user profile that is copied over
to all new pcs after they are built.
The problem im having is that all settings i have created
are applied other than the wallpaper, which comes up
blank. When i go into the display properties of the new
pcs the wallpaper is displayed in the desktops and themes
tabs, the apply button is greyed out and unless i change
another setting such as screen saver then apply it the
background will remain blank.