I have removed all the shadow tmp files (they were some 500 of them all over the place) and now I get different results
Load Poser, load Judy, Turn on ground, turn on shadows, render in firefly - No Shadows at all
Rebooted the system and tried again - no change, no shadows at all in firefly.
Weirdest thing now is that I cannot get any shadows at all in firefly. Raytrace shadows work fine, but no more depth map shadows.

Since deleting the shadow temp files did make a difference, I decided to restore some of the tmp files I deleted. And restoring "LIGHT1_shadow_0001.tmp" and the ones with similar names for lights 2 and 3 did bring back the old situation: Wrong shadows.
The files which I restored had a date of 20/2/2004, so from before installing SR4.

I am doing a very wild guess now - could it be that SR4 has problems creating a shadowmap temp file because of access rights or some other reason? None of the shadow temp files had a date stamp after the date of installing SR4.

For the record - I am using P5 SR4, Windows XP Pro.
I have checked the settings for the lights in the parameter dials (shadows set to 1.0, Cast shadows on), Ground settings (Cast shadows on), figure (Cast Shadows on), Render Settings Cast Shadows on.
I do not recall having these experiences with SR3

Is there anything else to check?