Using dgVoodoo 1.2 I got ground fog/haze colored black,brown and orange.

It formed a colored ring at ground level in a 360 degree ragged circle around the terrain.

In dgVoodoo setup,on the Glide setup page, the resolution was defaulted to 800x600. I changed this to match my in game setting of Glide/1074x768.

This corrected the problem as it has not reappeared after 2 game years worth of missions.

I am using the New 3d terrain vol files for
Red Baron 3D from:http://rensg.sqhq.net/

I have read the posts that recommend a different in game resolution from the desktop setting.What is the purpose of this? I have the setting same for both without problems...just curious as to what this is supposed to "fix."

AHAH! Looks like I won't be using dgVoodoo for a while. I get the circle of fog, but not colored, and the planes are invisible! My machine supports more than 800/600 but me ole monitor doesn't (my newer one broke).
It's been standard practice for a long time to run the different resolutions - it prevents a class of DTD's on some machines/systems,some are not affected with this bug. I run DT and RB at 800/600 with no problems so if yours is OK....."if it ain't broke"...
There is a wide range of DTD types,from the simple "return to DT" to "illegal program operattion"