if your path is drawn by hand you can't (unless whit a motion guide)
if your path is drawn by script the link you posted shoud by fine
or in F8 there woud by the possibility to scan the Path and move along
BUT this is realy have und CPU and also the logic behind it
i have try it a while ago not to hard and whit out to much suxes !
i think if i realy woud need to do it
I woud need atleast 1 week
of research and programing !