McGinley Dynamics

["Trey Johnson" <dickjohnson3@xxxxxxxxxxxxxx>]

 The code for this indicator in Kaufman's book, "Trading Systems and
Methods," is the following:

	inputs: k(.6),period(9);
	vars:MD(0);

		MD=MD[1]+(c-MD[1])/K*period*power((c/MD[1]),4);

		plot1(MD,"MD");

However, it doesn't work. I keep getting the error message: "attempt to
divide by zero." I tried a couple of different things and still can't get it
to work. Any suggestions?
Thanks in advance,
Trey Johnson