Mold Tooling Split: Rebuild Error "Cannot knit sheets together."

Hi all,

I'm trying to figure out why I keep getting the rebuild error "Cannot knit sheets together." while trying to make a tooling split of my cowling section.

I've tried it using the part as either a STEP or Parasolid....

Here's a screen shot.

All help will be appreciated.

Thanks....

SolidworksParts And Features