ftp -R 出現 tar error - Linux

mget/get/ftp -R 要下載一個目錄時 會遇到 tar xxxx error

ncftp / > mget -R source/
tar: This does not look like a tar archive
tar: Exiting with failure status due to previous errors
ncftp / >

整個目錄都沒下載到

這是server side的問題嗎 ?

--