imaptool: 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/imaptool - from package: imaptool

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

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