dh-make-ruby: 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-make-ruby - from package: gem2deb

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

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