Weird shadows and physics...

[wst50]

CPU: Athlon 64 3700+
OS: Win Xp home SP2

Problem;
I am using 2.8.5 alpha, and downloaded some planes for it. One of the palnes, whether model crashes are allowed or not, whenever it crashes goes into a random spin underground- and cannot be retrieved with I or f2. Also, the shadows are blue, and an SR-71 I downloaded sits on it's belly when on the ground, and the undercarraige is underground.