xbindkeys: 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/xbindkeys - from package: xbindkeys

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

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