ninpaths: command not found

Maybe Your $PATH variable doesn't contain the default paths? echo $PATH should give something like:

[root@server ~]# echo $PATH
/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin

If it's empty, You may set the PATH variable with this command

export PATH="/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin"

On Debian possible default full paths are:

/usr/lib/news/bin/ninpaths - from package: inn2

You may install the required package with command apt-get install {package}

Error in other languages:
ninpaths: bevel nie gevind nie
ninpaths: comandă negăsită
ninpaths: comando não encontrado
ninpaths: commande introuvable
ninpaths: command not found
ninpaths: käsku ei ole
ninpaths: không tìm thấy lệnh
ninpaths: komanda nerasta
ninpaths: Kommando nicht gefunden.
ninpaths: kommandot finns inte
ninpaths: komut yok
ninpaths: nie znaleziono polecenia
ninpaths: níor aimsíodh an t-ordú
ninpaths: no se encontró la orden
ninpaths: no s'ha trobat l'ordre
ninpaths: opdracht niet gevonden
ninpaths: parancs nem található
ninpaths: perintah tidak ditemukan
ninpaths: príkaz nenájdený
ninpaths: příkaz nenalezen
ninpaths: команда не найдена
ninpaths: командата не е открита
ninpaths: 命令找不到
ninpaths: コマンドが見つかりません