I am trying to run Simplify Line on some contours. I have run both "Check Geometry" and "Repair Geometry", to fix any topological errors. I keep getting the error: "Invalid Topology (Feature not found on delete.)" I have even tried this on a tiny subset of my data, and I still get the error.
I am using ArcGIS for Desktop Advanced, version 10.1 SP 1.
I have attached my test data as a zip file containing an xml workspace document of the feature class. I have also attached a jpeg showing a screen shot of the results tab, including the error message.