dh_desktop: 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_desktop - from package: debhelper

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