upstart-socket-bridge: command not found

Have You tried accessing the binary with the full path?

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:

/sbin/upstart-socket-bridge - from package: upstart

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