Hi! I tried to replicate an example on the tutorials. https://www.stata.com/manuals13/rgmm.pdf (Example 12).
The code is
Array

I copied this program and then run the code below.

use http://www.stata-press.com/data/r13/poisson2
gmm gmm_poiend, nequations(1) vce(cluster id) onestep > parameters(y:x1 y:x2 y:x3) instruments(x1 x2 L2.x3, noconstant)

but it showed that ‘mu’ invalid name.

Can anyone tell me why this happened? Thanks.