1. Draw your path in max...
2. Draw your shape
3. select path, geometry > compound objects > loft > get shape > click on shape, loft made
4. Use scale deformation in modify panel to animate the loft, this is not the most accurate
way to do this though. there is another way..., apparently there is a new way to loft
along a path in max 7 called sweep.
"An easy way to animate a growing surface is to put a curve point with trimming on a curve, then animate the U position of the curve point, and then use this curve as the rail of a 1-rail sweep. As the trimmed rail grows, so does the sweep surface. (You must trim the curve before you create the sweep surface.)"