Win2003 HAL filtering problem

We upgraded the first of our RIS servers from Win2000 to Win2003 last night.
Now only the flat images show up as choices when trying to RIS a
workstation, none of the sysprep images created with riprep show up. The HAL
filtering that 2003 performs seems to be broken, because

a) an image I created a few days ago from a Dell GX270 workstation does not
appear as a choice when I try to image that same workstation with RIS.

b) if I comment out the halname=halaacpi.dll line from the [OSChooser]
section in riprep.sif for that image, then the image shows up as a choice
and I can install it to the workstation without error.

c) I used riprep on the upgraded server to create a new image from a
workstation, and then PXE booted that exact same workstation, but the image
just created did not show as a choice. Commenting out the halname= line
again fixed the problem.

Is there an alternative solution to having to modify the sif files to get
our images to display?

Nick Payne
nickDOTpayne@afp.gov.au