dh_pidgin: 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_pidgin - from package: pidgin-dev

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

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