Set Smooth - need help

I’m trying to model a head but there’s one problem with Set Smooth i can’t get rid of.
Sometimes some (SubSurved) faces have grey edges.

See http://gif.250kb.de/6afb00f3f153760e0b4df47e12e711b0.gif to see what i mean.

Would be nice if you helped me.

Select all the faces of the model and press ctrl N to recalculate normals outside.

yes it worked!!! thank you.