multitail: 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/multitail - from package: multitail

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

On Debian possible default full paths are:

/usr/bin/multitail - from package: multitail
/usr/share/storebackup/bin/multitail - from package: storebackup

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

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