dsolve system with boundary conditions

Hi

I'd like to see the solutions of this system of differential equation with boundary conditions :

restart;
with(PDEtools);
EDP := diff(s(z), z) = -.45*i(z)*s(z), diff(i(z), z) = .45*i(z)*s(z)-.2*i(z)-.8*(diff(i(z), z));
IBC := s(100) = 1, (D(i))(100) = 0

But, when i do : dsolve({EDP, IBC}, numeric, range = 0 .. 100);

I receive the error : Error, (in dsolve/numeric/bvp) unspecified error
 
 

Do you have a solution of my problem ?

And do you know how i can plot the soltions ?

Thanks a lot !