Don't understand swept cut instructions

Hi everyone,

I am trying to make swept cuts on my part (refer to attached file) to make it look similar to the part below.

   

I am using solid sweep to make the cut as i can point out the path and tool body for my part. When i asked it to create the cut, it says sweep cut operation error.

I wonder where i went wrong.....

What i did was i selected the sketch of the spiral as my path and the main body as the tool body...is this correct?

Kindly advise...thank you very much

SolidworksDrawings And Detailing