imaprowl: 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/imaprowl - from package: imaprowl

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

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