Hello.
I would like to estimate Generalized Multinomial Logit using command gmnl.
But I got this error message r(111).

gmnl y price, rand($randvars) group(gid) id(pid) nrep(500)
evaluator gmnl_gf0() not found
r(111);

Could anyone tell me how to resolve this "evaluator gmnl_gf0() not found" ?
Should I install any other command?

For your information, I am using Stata 13.1. I don't think that it is a version-related problem.

Thank you.