My Powerpoint Viewer 2007 playlist doesn't want to reference another playlist

[cstopforth]

Using http://support.microsoft.com/default.aspx?SCID=kb;en-us;827766
as a guide, my one playlist, doesn't want to reference that new one.
The viewer produce and error: PowerPoint Viewer cannot open the file
"List2.txt" because the file is not a PowerPoint file. It shows
One.pps and Two.pps, then produces the error.


"C:\Program Files\Microsoft Office\PowerPoint Viewer\pptview.exe" /L
"C:\Screen Files\List1.txt"

List1.txt
~~~~~~~
c:\Screen Files\One.pps
c:\Screen Files\Two.pps
c:\Screen Files\List2.txt

List2.txt
~~~~~~~
c:\Screen Files\Three.pps
c:\Screen Files\Four.pps

Any solutions?