Artificial neural network training error

am trying to train may network for four inputs and two outputs every time i run a code ans is different and accuracy is poor

here is the code

input=load('input.csv');

target=load('target.csv');

in=input';

tar=target';

net=feedforwardnet(8);

[net,tr]=train(net,in,tar);

ytrain=net(in(:,tr.trainInd));

testdata=[1;0.16;420;89.7];

[Target]=net(testdata);

a = Target (1,1);

b = Target (2,1);

X = [' The predicted a is: ',num2str(a)];

disp(X)

X = [' The predicted b is: ',num2str(b)];

disp(X)