sendmsg: 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/sendmsg - from package: sendfile

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

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