nntp-push: 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/bin/nntp-push - from package: sinntp

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

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