supfilesrv: 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/supfilesrv - from package: sup

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

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