Help Convert Code

[astronomia84]

Please Help Convert This Code.
I've got this program

-> http://elib.zib.de/pub/elib/hairer-wanner/nonstiff/dr_dop853.f

->http://elib.zib.de/pub/elib/hairer-wanner/nonstiff/dop853.f

that works in fortran, but only for n=2 dimension (system)
e.g van der Pol Equation (http://mathworld.wolfram.com/vanderPolEquation.html)
How to convert this code for some problems with n=4 dimensions?
What new default values for parameters ?
o:)