xenstore-ls: 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/sbin/xenstore-ls - from package: xenstore-utils

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

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