userformat: 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 CentOS possible default full paths are:

/usr/bin/userformat - from package: usermode-gtk

You may install the required package with command yum install {package}

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