cvm-vmailmgr: 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/cvm-vmailmgr - from package: cvm

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

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