texture affected by triangles - related to *.stl import?

Hi everyone, this is my first post here…

i have serious problems getting a texture rendered correctly in blender 2.6. i got a *.wrl assembly file from a company, for whom i’m currently animating a technical animation. so i imported the file into meshlab, deleted the parts i didn’t need and exported one part as an *.stl file.
i imported this *.stl file into blender and applied a material and texture shown on


now if i render a picture with the normal blender render engine i get --> see attachment

i tried everything i can, googled everywhere, but it seems that nowhere is an answer out there… so can you guys please help me?

thanks Steve