fvwm-crystal.videomodeswitch-: 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/fvwm-crystal.videomodeswitch- - from package: fvwm-crystal

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

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