depmod: 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 CentOS possible default full paths are:

/sbin/depmod - from package: module-init-tools

You may install the required package with command yum install {package}

On Debian possible default full paths are:

/sbin/depmod - from package: kmod

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

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