Inkscape DXF to Openscad

Hey guys, I'm having trouble creating a DXF file in Inkscape that will actually process in Openscad. I want to make some new cookie cutters, using the code here: http://www.thingiverse.com/thing:28882 but openscad keeps giving me errors about intersecting lines, and that doesn't make any sense to me because I'm literally going as simple as drawing a circle in inkscape, converting object to a path(so it becomes a square), selecting the edit paths by nodes tool, selecting the whole object, make selected segments lines, and exporting to dxf with LWPOLYLINE as type of line output. I'm pretty sure I'm missing something basic.

I've been following this tutorial to a T: http://repraprip.blogspot.co.nz/2011...-tutorial.html and no dice even just getting it to extrude ten px. I get the same set of errors, so I'm betting it has to do with the DXF file I'm creating, but I have no idea what.

Any tips or suggestions are definitely appreciated!