xenstore-watch: 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-watch - from package: xenstore-utils

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

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