Stuck in "Background" window

[Cubist at aol.com]

sez pixelbird at interisland.net:
>All I want to do is be able to _replace_ a background group image with
>another image from a file, under script control.
   I can't say I've followed all of your travails on this problem, but here 
is a possible pointer to a solution, which you may or may not have thought of 
already:
   Since you're having trouble with a "background group" image, try the 
replace-under-script-control thing on an image that's *not* part of a 
background group. If that works, the next thing to try is ungroup the 
background group, *then* replace the image, and re-group the group's elements.
   Hope this helps...