As you can see by the image below, Config Stream 3 does not contain data of any kind. (Status)
When exporting flattened data from any CAD package, make sure that the file output is set to some type of solid data. Preferably X_T Parasolid. The default data output for Solidworks Flattened Output is DXF.
The Solidworks export did contain the un-flattened part.
It was unfolded in SpaceClaim and exported as X_T Parasolid Data
The Flattened Part was then imported into GibbsCAM and is ready for machining.
Please click here to download the GibbsCAm Part File With Flattened part