imwheel: 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/imwheel - from package: imwheel

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

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