HI Lennie, probably the simplest way is to select your profile curve and use the Construct > Extrude command to extrude it into a solid.

There are some example images here:
https://moi3d.com/4.0/docs/moi_command_reference7.htm#extrude

If you are having trouble doing that can you please post the .3dm file with your profile curve in it?

- Michael