Had this happen to me on a CRJ
I've discovered that this seems to be happening to some add-on DDS textues. What's odd is that I have two versions of the camo 737. One in the native 737-800 folder, and one with a re-worked .cfg as it's own stand alone aircraft (AC-40A "Wraith" gunship) The one in the native 747-800 folder works fine, the "Wraith" is messed up.
Just yesterday I was fiddling around and wanted to repaint the "white" Grumman goose as "Cutters Goose" from the TV series, "Tales from (Or "of") the Gold Monkey, and it turned displays as a "junkyard" model (Besides not displaying the repainted fusalage. Just a black shape).
I just tried downloading a repaint of the CRJ-700, added it, same results: Junkyard
This does not seem to be happening with BMP textures, however, though I need to double check that.
How did you fix the "junkyard" effect?