winswitch_client: 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/winswitch_client - from package: winswitch

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

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