Hi, I am developing a frontier model but am unable to predict inefficiency and efficiency values. Below I've copied my instructions:

. xtfrontier frlabreg edu gdppcavg d.act year, ti

[results ommitted for simplicity]

. sort countrynum

. predict fcastti, xb
(36 missing values generated)

. predict inefti, u
not sorted
r(5);

Can you help?
Many thanks