gimptool-2.0: 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 CentOS possible default full paths are:

/usr/bin/gimptool-2.0 - from package: gimp-devel-tools

You may install the required package with command yum install {package}

On Debian possible default full paths are:

/usr/bin/gimptool-2.0 - from package: libgimp2.0-dev

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

Error in other languages:
gimptool-2.0: bevel nie gevind nie
gimptool-2.0: comandă negăsită
gimptool-2.0: comando não encontrado
gimptool-2.0: commande introuvable
gimptool-2.0: command not found
gimptool-2.0: käsku ei ole
gimptool-2.0: không tìm thấy lệnh
gimptool-2.0: komanda nerasta
gimptool-2.0: Kommando nicht gefunden.
gimptool-2.0: kommandot finns inte
gimptool-2.0: komut yok
gimptool-2.0: nie znaleziono polecenia
gimptool-2.0: níor aimsíodh an t-ordú
gimptool-2.0: no se encontró la orden
gimptool-2.0: no s'ha trobat l'ordre
gimptool-2.0: opdracht niet gevonden
gimptool-2.0: parancs nem található
gimptool-2.0: perintah tidak ditemukan
gimptool-2.0: príkaz nenájdený
gimptool-2.0: příkaz nenalezen
gimptool-2.0: команда не найдена
gimptool-2.0: командата не е открита
gimptool-2.0: 命令找不到
gimptool-2.0: コマンドが見つかりません