x2vnc: 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/x2vnc - from package: x2vnc

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

Error in other languages:
x2vnc: bevel nie gevind nie
x2vnc: comandă negăsită
x2vnc: comando não encontrado
x2vnc: commande introuvable
x2vnc: command not found
x2vnc: käsku ei ole
x2vnc: không tìm thấy lệnh
x2vnc: komanda nerasta
x2vnc: Kommando nicht gefunden.
x2vnc: kommandot finns inte
x2vnc: komut yok
x2vnc: nie znaleziono polecenia
x2vnc: níor aimsíodh an t-ordú
x2vnc: no se encontró la orden
x2vnc: no s'ha trobat l'ordre
x2vnc: opdracht niet gevonden
x2vnc: parancs nem található
x2vnc: perintah tidak ditemukan
x2vnc: príkaz nenájdený
x2vnc: příkaz nenalezen
x2vnc: команда не найдена
x2vnc: командата не е открита
x2vnc: 命令找不到
x2vnc: コマンドが見つかりません