Need help modeling a strand - Twisting a sweep along a helical path

Hi all -

I've had a very frustrating problem the last few days that I can't get figured out.  I need to model a 3 x 7 strand.  The 3 means there are 3 wires twisted together into a strand - like this:

And then 7 of these "3 wire" strands are then wound together, with 6 fitting snuggly around the edge of the middle 1 (like a hexagon with something in the middle)

So, I'm starting with the above image, then going into something like this:

Sweeping along a helical path, which I would then pattern 6 times around the central one.

BUT, if you can see the problem...  the outer strand won't "twist" like the central one!  When I try to "twist along path" for the sweep, it says "sweep operation failed to complete.  Smooth path is needed for sweep with twist"

Please help!  I can't figure out what this means or what the problem is.  Is there another way to accomplish this without "sweeping with a twist"?  Any help is much appreciated.

SolidworksSurfacing