Question: Warning, limiting number of function evaluations reached

restart;
with(plots):
with(Optimization):
with(LinearAlgebra):
with(Statistics):
with(DEtools):
x11 := <0.208408965651696e-3, -0.157194487523421e-2, -0.294739401402979e-2, 0.788206708183853e-2, 0.499394753201753e-2, 0.191468321959759e-3, 0.504980449104750e-2, 0.222150494088535e-2, 0.132091821964287e-2, 0.161118434883258e-2, -0.281236534046873e-2, -0.398055875132037e-2, -0.111753680372819e-1, 0.588868146012489e-2, -0.354191562612469e-2, 0.984082837373291e-3, -0.116041186868374e-1, 0.603027845850267e-3, -0.448778128168742e-2, -0.127561485214862e-1, -0.412027655195339e-2, 0.379387381798949e-2, -0.602550446997765e-2, -0.605986284736216e-2, -0.751396992404410e-2, 0.633613424008655e-2, -0.677581832613623e-2>;
y11 := <-21321.9719565717, 231.709204951251, 1527.92905167191, -32.8508507060675, 54.9408176234139, -99.4222178124229, -675.771433486265, 42.0838668074923, -12559.3183308951, 5.21412214166344*10^5, 1110.50031772203, 3.67149699000155, -108.543878970269, -8.48861069398811, -521.810552387313, 26.4792411876883, -8.32240296737599, -1085.40982521906, -44.1390030597906, -203.891397612798, -56.3746416571417, -218.205643256096, -178.991498697065, -42.2468018350386, .328546922634921, -1883.18308996621, 111.747881085748>;
z11 := <1549.88755331800, -329.861725802688, 8.54200301129155, -283.381775745327, -54.5469129127573, 1875.94875597129, -16.2230517860850, 6084.82381954832, 1146.15489803104, -456.460512914647, 104.533252701641, 16.3998365630734, 11.5710907832054, -175.370276462696, 33.8045539958636, 2029.50029336951, 1387.92643570857, 9.54717543291120, -1999.09590358328, 29.7628085078953, 2.58210333216737*10^6, 57.7969622731082, -6.42551196941394, -8549.23677077892, -49.0081775323244, -72.5156360537114, 183.539911458475>;
ICS:=[x1(0)=x11[1],y1(0)=y11[1],z1(0)=z11[1]];
N := Dimension(x11)-1:
sys1 := [Diff(x1(t),t) = k1*x1(t)+ k2*y1(t)+ k3*z1(t), Diff(y1(t),t) = k5*x1(t)+ k6*y1(t)+ k7*z1(t), Diff(z1(t),t) = k9*x1(t)+ k10*y1(t)+ k11*z1(t)];
SS := proc(k1,k2,k3,k5,k6,k7,k9,k10,k11)
local F, V;
if not type([k1,k2,k3,k5,k6,k7,k9,k10,k11],[numeric,numeric,numeric,numeric,numeric,numeric,numeric,numeric,numeric]) then return 'SS'(k1,k2,k3,k5,k6,k7,k9,k10,k11);
elif k1<0 or k2<0 or k3<0 or k5<0 or k6<0 or k7<0 or k9<0 or k10<0 or k11<0 then return 1e100;
end if;
F := dsolve(eval({Diff(x1(t),t) = k1*x1(t)+ k2*y1(t)+ k3*z1(t), Diff(y1(t),t) = k5*x1(t)+ k6*y1(t)+ k7*z1(t), Diff(z1(t),t) = k9*x1(t)+ k10*y1(t)+ k11*z1(t),x1(0)=x11[1],y1(0)=y11[1],z1(0)=z11[1]},{:-k1=k1,:-k2=k2,:-k3=k3,:-k5=k5,:-k6=k6,:-k7=k7,:-k9=k9,:-k10=k10,:-k11=k11}), [x1(t),y1(t),z1(t)], numeric, output=Array([seq(k,k=0..N)]));
V := convert(Column(F[2,1],2),Vector);
Norm(V-x11,2);
Norm(V-y11,2);
Norm(V-z11,2);
end proc:
params := NLPSolve(SS(k1,k2,k3,k5,k6,k7,k9,k10,k11), method=nonlinearsimplex, initialpoint=[k1=.1, k2=.1, k3=.1, k5=.1, k6=.1, k7=.1, k9=.1, k10=.1, k11=.1],evaluationlimit=200):

Warning, limiting number of function evaluations reached

reference from 

http://www.maplesoft.com/applications/view.aspx?SID=1667

when debug

k1=.1; k2=.1; k3=.1; k5=.1; k6=.1; k7=.1; k9=.1; k10=.1; k11=.1;
F := dsolve({Diff(x1(t),t) = k1*x1(t)+ k2*y1(t)+ k3*z1(t), Diff(y1(t),t) = k5*x1(t)+ k6*y1(t)+ k7*z1(t), Diff(z1(t),t) = k9*x1(t)+ k10*y1(t)+ k11*z1(t),x1(0)=x11[1],y1(0)=y11[1],z1(0)=z11[1]}, [x1(t),y1(t),z1(t)], numeric, output=Array([seq(k,k=0..N)]));

Warning, The use of global variables in numerical ODE problems is deprecated, and will be removed in a future release. Use the 'parameters' argument instead (see ?dsolve,numeric,parameters)
Error, (in dsolve/numeric) Array/array solutions cannot be obtained for ODE containing unassigned global variables {k1, k10, k11, k2, k3, k5, k6, k7, k9}