运行lingo程序出现unexpected jacobian

运行lingo程序出现unexpected jacobian
model:
min=max(T1..T5);
n1*8+2*((k1-1)*3.2+4.8)/1.6*x1=T1;
n2*8+2*((k2-1)*3.2+4.8)/1.6*x2=T2;
n3*8+2*((k3-1)*3.2+4.8)/1.6*x3=T3;
n4*8+2*((k4-1)*3.2+4.8)/1.6*x4=T4;
n5*8+2*((k5-1)*3.2+4.8)/1.6*x5=T5;
k5=28;
@bnd(1,k1,k2);
@bnd(k1,k2,k3);
@bnd(k2,k3,k4);
@bnd(k3,k4,k5);
@gin(k1);@gin(k2);@gin(k3);@gin(k4);
n1=0.5*(k1-1);
n2=0.5*(k2-k1);
n3=0.5*(k3-k2);
n4=0.5*(k4-k3);
n5=0.5*(k5-k4);
x1=(k1-1)*100/18;
x2=(k2-k1)*100/18;
x3=(k3-k2)*100/18;
x4=(k4-k3)*100/18;
x5=(k5-k4)*100/18;
end