xenstore-control: 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

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/lib/xen-4.4/bin/xenstore-control - from package: xen-utils-4.4

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