kvg: command not found

Have You tried accessing the binary with the full path?

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 CentOS possible default full paths are:

/usr/bin/kvg - from package: mgetty-sendfax

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