Why does WMP10 distort this MPG?

I produced an MPG test file in Womble MPEG Video Wizard. I've uploaded
it here (26MB):
http://www.speedyshare.com/617700187.html

As you see from this GSpot report extract, its size is 640x480, i.e.
an AR of 4:3.

--- Video Information --- Video Codec Type(e.g. "DIV3"):
MPEG2
Video Codec Name(e.g. "DivX 3, Low-Motion"): MPEG-2
Video Codec Status(e.g. "Codec Is Installed"): Codec(s) are Installed
Duration (hh:mm:ss): 0:02.000 Frame Count:
50
Frame Width (pixels): 640
Frame Height (pixels): 480
Storage Aspect Ratio("SAR")" 1.333 Pixel Aspect
Ratio ("PAR"):
Display Aspect Ratio ("DAR"):
Fields Per Second: 50.000
Frames Per Second: 25.000
Pics Per Second: 25.000
Video Bitrate (kbps): 33554

It plays fine in various of my players - except WMP10, where it
displays square instead of 4:3. Is there some setting I've so far not
found in WMP10 that is causing this please?

--
Terry, East Grinstead, UK