Duplicating an object over a curve in Maya
In order to duplicate an object over a curve you have to do the following in Maya
1. Create a curve
2. Create an object
3. Attach that object to the curve (Animate>Motion Path> Attach to Motion Path)
4. Play the animation selecting the object then duplicating it (SHIFT+D) on the specified frame.
Keep doing this all over again until you duplicate all the desired objects, then simply select the curve and the main object and delete them.