What the problem is and what the tool does:
The skin lines are caused by some kind of mismatch of the mesh tangents calculated by Milkshape at the seams. If you look closely at EA meshes vs Milkshape-edited meshes, there are also more subtle differences in the way the muscle definition appears. This tool recalculates the tangents for the entire mesh. The results are not identical to the EA values, but the appearance is much closer to the EA meshes and the skin seams are fixed.
Read more and download at Mod The Sims
