dh_di_kernel_install: 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 Debian possible default full paths are:

/usr/bin/dh_di_kernel_install - from package: dh-di

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