xcontrol: 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/xcontrol - from package: debian-xcontrol

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

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