choosewm: 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/choosewm - from package: choosewm

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

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