I made a medium sized circle and pasted it to the clipboard. I then used the Bezier tool set to spiropath and the shape on from clipboard. However, when I drew my line, curving it with the bezier, it completely filled in the stroke. I've checked path effects, and there is no options there that have helped me. Here is a screenshot of my problem.

The circle on the top left corner is the object I pasted on the clipboard. The large blob in the center is the spiropath I drew in the center, but instead of using the circle, and filled in the edges. Also, if its of any relevance, I use a mac.