grub-syslinux2cfg: 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

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/grub-syslinux2cfg - from package: grub-common

You may install the required package with command apt-get install {package}
Error in other languages:
grub-syslinux2cfg: bevel nie gevind nie
grub-syslinux2cfg: comandă negăsită
grub-syslinux2cfg: comando não encontrado
grub-syslinux2cfg: commande introuvable
grub-syslinux2cfg: command not found
grub-syslinux2cfg: käsku ei ole
grub-syslinux2cfg: không tìm thấy lệnh
grub-syslinux2cfg: komanda nerasta
grub-syslinux2cfg: Kommando nicht gefunden.
grub-syslinux2cfg: kommandot finns inte
grub-syslinux2cfg: komut yok
grub-syslinux2cfg: nie znaleziono polecenia
grub-syslinux2cfg: níor aimsíodh an t-ordú
grub-syslinux2cfg: no se encontró la orden
grub-syslinux2cfg: no s'ha trobat l'ordre
grub-syslinux2cfg: opdracht niet gevonden
grub-syslinux2cfg: parancs nem található
grub-syslinux2cfg: perintah tidak ditemukan
grub-syslinux2cfg: príkaz nenájdený
grub-syslinux2cfg: příkaz nenalezen
grub-syslinux2cfg: команда не найдена
grub-syslinux2cfg: командата не е открита
grub-syslinux2cfg: 命令找不到
grub-syslinux2cfg: コマンドが見つかりません