xen-create-nfs: 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/xen-create-nfs - from package: xen-tools

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

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