Im newbie to Maple and trying to solve the following pde numerically:

PDE:=diff(u(t,z),t )-v*diff(u(t,z),z) = D*diff(u(t,z),z$2 z)z) -k*u(t,z);
ics := {D*`∂`(u(t, 0))/`∂`(z) = v*(C-u(t, 0)), D*`∂`(u)*(t, L)/`∂`(z) = 0, u(t, 0) = C};

sol := pdsolve(eval(PDE, {D = 1, k = 1, v = 1}), eval(ics, {C = 10, D = 1, L = 1, v = 1}), numeric, time = t, range = 0 .. 1);
Error, (in pdsolve/numeric/process_IBCs) improper op or subscript selector

I do not know how to correct this error. PLease help. Thank you.