GeomFill_Pipe produces artefacts

Hello guys!

I am using the class GeomFill_Pipe to create a tube with a constant radius. It works well for most simple paths, but if the the path (GeomBSpline_Curve) gets more complex, the resulting tube contains some artefacts. Heres my code snippet:
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Handle(Geom_Curve) c = BRep_Tool::Curve(the_edge,first,last);
Handle(Geom_TrimmedCurve) tc = new Geom_TrimmedCurve(c,first,last);
GeomFill_Pipe gfp(tc,_radius);
gfp.Perform(Precision::Confusion(),Standard_False,GeomAbs_C1,BSplCLib::MaxDegree(),1000);
BRepBuilderAPI_MakeFace aFaceBuilder(gfp.Surface(),Precision::Confusion());
if(aFaceBuilder.Error() != BRepBuilderAPI_FaceDone)
{
//error
}
TopoDS_Shape theResult = aFaceBuilder.Shape()
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Should I use an alternative class to GeomFill_Pipe?

I am using OCC 6.7.1 on Windows 7 (x64).

Thanks in advance!

Regards,
Alex