Sweep Cut using a helix

Hi Guys

I'm trying to design a bowl to be machined on a CNC router and I want to cut a spiral inside the bowl.  I set up a helix and a cut profile but I just keep getting the message "Sweep operation failed to complete".

Using the same sketches I can sweep a solid but I can't make a cut, any ideas?

I've attached a file.

Regards

Dave K

SolidworksParts And Features