Recently I tried to perform a cut-extrude operation on a sketch segment of my pelvis part of a humanoid robot. However, the feature could not be created due to zero-thickness geometry, as stated in the error. I have no idea why this is the case. No edges are intersecting with zero thickness, none that I notice. Here is an image of the error itself:

My sketch itself is made of an offset contour of the extrude itself, joined by splines to close the sketch. 

Attached below is my assembly packaged. Any help would be very much appreciated.