Question: fslove dosn`t work whit some variable

Hi/

the code below wroten by Maple 13. I use h=0.29669 and N:=15 and digit=80 fsolve works perfect! but when I changed N:=16 and another number greater than 15 fsolve didnt return result and return some equation.

whould you help me how to resolve this problem?

sorry i upload this code. to run easilySinc_MBVP_V2-temp.mw

thanks

> restart;
> N := 15;
> Digits := 80;
> h := .29669;
> delta[0] := proc (k, j) options operator, arrow; piecewise(k = j, 1, k <> j, 0) end proc;
> delta[1] := proc (k, j) options operator, arrow; piecewise(k = j, 0, k <> j, (-1)^(j-k)/(j-k))/h end proc;
> delta[2] := proc (k, j) options operator, arrow; piecewise(k = j, -(1/3)*Pi^2, k <> j, -2*(-1)^(j-k)/(j-k)^2)/h^2 end proc;
> phi := proc (x) options operator, arrow; ln(sinh(x)) end proc;
>
> w := proc (x) options operator, arrow; x end proc;
>
>
> pl := a*x^2+1;
>
>
>
> u := c[j]*x;
> NULL;
> u1 := sum(c[k]*(w(x)*(diff(phi(x), x))*delta[1](k, j)+delta[0](k, j)), k = -N .. N);
> u2 := sum(c[k]*((2*(diff(phi(x), x))+w(x)*(diff(phi(x), x, x)))*delta[1](k, j)+w(x)*(diff(phi(x), x))^2*delta[2](k, j)), k = -N .. N);
> y := u+pl;
> y;
                                          2    
                              c[j] x + a x  + 1
> y1 := u1+diff(pl, x);
> y2 := u2+diff(pl, x, x);
> m := 2.5;
> R := x*y2+2*y1+x*y^m;
> NULL;
> i := 0;
> for j from -N-1 to N do if j = -N-1 then c[j] := 0 end if; i := i+1; v := ln(exp(j*h)+sqrt(exp(2*j*h)+1)); EQ[i] := evalf(subs(x = v, R)) end do;
> i;
                                     32
> NULL;
> NULL;
>
> i := 'i';
                                      i
>
> X := solve({seq(EQ[i], i = 1 .. 2*N+2)}, {a, seq(c[k], k = -N .. N)});