I downloaded a FSX mission, worlds toughest landings....LuKLA Airport in Nepal. I came with the dehavilland Otter. I completed the download, and then placed the folders in the correct FSX folder (I think I did anyway), but when I started the mission, I only showed the plane, but no paint.
I thought I'd be tricky, so I went back and found another Otter and downloaded it. Then I installed it in the FSX airplanes folder, and removed the plane that came with the mission. Restarted FSX and the same thing happened...got the plane, but no texture.
Go into the Sims menu, choose the graphics tab and uncheck the box that say's DX10.