dh_apache2: 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 Debian possible default full paths are:

/usr/bin/dh_apache2 - from package: apache2-dev

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

Error in other languages:
dh_apache2: bevel nie gevind nie
dh_apache2: comandă negăsită
dh_apache2: comando não encontrado
dh_apache2: commande introuvable
dh_apache2: command not found
dh_apache2: käsku ei ole
dh_apache2: không tìm thấy lệnh
dh_apache2: komanda nerasta
dh_apache2: Kommando nicht gefunden.
dh_apache2: kommandot finns inte
dh_apache2: komut yok
dh_apache2: nie znaleziono polecenia
dh_apache2: níor aimsíodh an t-ordú
dh_apache2: no se encontró la orden
dh_apache2: no s'ha trobat l'ordre
dh_apache2: opdracht niet gevonden
dh_apache2: parancs nem található
dh_apache2: perintah tidak ditemukan
dh_apache2: príkaz nenájdený
dh_apache2: příkaz nenalezen
dh_apache2: команда не найдена
dh_apache2: командата не е открита
dh_apache2: 命令找不到
dh_apache2: コマンドが見つかりません