If you have access to a modeling program, you need to add a very thin ring og polygons around the problem areas. In Lightwave, you can ussally select the the edges and do an "edge bevel". This will raise the poly count slightly, but cleans up those wierd render errors pretty well.

mo·nop·o·ly  [muh-nop-uh-lee]
noun, plural mo·nop·o·lies.
1. exclusive control of a commodity or service in a particular market,
or a control that makes possible the manipulation of prices