blend-update-usermenus: 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/blend-update-usermenus - from package: blends-common

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

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