Depends on what aircraft its for, but I bet the textures need to be in DXT3 format and they aren't.  DXT3 is what FS uses to make reflective textures, using an alpha channel that is the reflective layering.  The darker the shade on the alpha channel (256 grayscale) the more it relfects.  Black is mirror and white is matte.  I would suggest you go find this item and also read up on any repainting documentation you can find.

Also, make sure the aircraft.cfg file is in the correct order.  If something is out of whack in the ui section (the one that has [fltsim.x] at the beginning) then there will inevitably be problems.  You have to set it up a certain way.  I don't have enough time to show you how right now, but I will return later today to see if you have figured out the issues.