In GibbsCam 2010 V9.5 this model shows up not as a solid but as a shell. (10-00188F)
This problem doesn’t occur by all models. (10-00188H)
You skipped "Sketch -30 Grad" in your loft
A step export and import to Rhino shows a bad surface near the skipped sketch
Can't say absolutely that that's your problem but worth fixing to see.