wimenu: command not found

Have You tried accessing the binary with the full path?

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/wimenu - from package: wmii

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