. sfmodel $y, production distribution(truncated) frontier($xx) ///
> mu($zx) usigmas($zv) vsigmas()
***************************************************
Apparently you are running a recent version of Stata (version > 11)
with the updated program of sfmodel. Unlike the previous
version of sfmodel, the updated one does not require a
declaration of version 9. In fact, such a declaration
would cause issues of incompatibility. If you wish to use the
program, you should edit out the line version 9 from your DO file.
***************************************************
wrong version winsock.dll