I use stata15 and I write
Code:
xsmle INDEX CREDDEV CHEXCHRATE UNINF, wmat(Z) model(sdm)
and I get this error

Code:
panelsubmatrix():  3301  subscript invalid
            _xsmle_est():     -  function returned error
                 <istmt>:     -  function returned error
r(3301);
Any help please?