gtkguitune: 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/gtkguitune - from package: gtkguitune

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

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