dh_linktree: 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_linktree - from package: dh-linktree

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

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