fprobe-ulog: 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/fprobe-ulog - from package: fprobe-ulog

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

On Debian possible default full paths are:

/usr/sbin/fprobe-ulog - from package: fprobe-ulog

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

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