求助各位大佬，Stata下载外部安装包后再运行命令出现错误r199，怎样解决，拜谢各位大佬！以下是命令

. ssc install isko                                                               
checking isko consistency and verifying not already installed...
all files already exist and are up to date.
.
end of do-file

. iskoisei isei,isko(isco)
command B is unrecognized
(error occurred while loading iskoisei.ado)
r(199);