Inputs for the train should be R-by-Q matrix where R is input size and Q is batch size. Input size is 900x4 (Q- 900 and R-4) and target size is 900x2(Q-900 and R-2) in your case. So there is no issue with the below line
net = train (net, input', target');
But the lines
y = net(input);
perf = perform(net,y,target)
will give you an error because sizes don’t match. You could try using transpose for both input and target.
y = net(input');
perf = perform(net,y,target');
Hope this helps!