wmii.sh: 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/wmii.sh - from package: wmii

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

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