Hi TweenGuy
I am new to the cow, but I will do my best in repley, and I am sure others may have other ways to do this.
1)Copy the key frame or frames of your path (or mask) to an adjustment layer.
2)Then go to you layer that contains the shine effect and alt click on the Source point
to create an expression line.
3)Then attach your expression to the position of of the new adjustment layer that you created. (adjust keyframes if needed)
Hope this helps!
Videobill