fill_test: 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/fill_test - from package: srm

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

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